Acid2
Encyclopedia
Acid2 is a test page published and promoted by the Web Standards Project
to expose web page
rendering
flaws in web browser
s and other applications that render HTML
. Named after the acid test for gold
, it was developed in the spirit of Acid1
, a relatively narrow test of compliance with the Cascading Style Sheets
1.0 (CSS1) standard, and was released on April 13, 2005. As with Acid1, an application passes the test if the way it displays the test page matches a reference image.
Acid2 tests aspects of HTML markup, CSS 2.1 styling, PNG images, and data URIs. The Acid2 test page will be displayed correctly in any application that follows the World Wide Web Consortium
and Internet Engineering Task Force
specifications for these technologies. These specifications are known as web standards
because they describe how technologies used on the web are expected to function.
While at the time of Acid2's release no web browser passed the test, Acid2 was designed with Microsoft Internet Explorer particularly in mind. The creators of Acid2 were dismayed that Internet Explorer did not follow web standards, and that because of this, Internet Explorer was prone to display web pages differently from other browsers. When such a discrepancy between browsers is encountered, web developers spend time tweaking
their web pages in order to make the pages be displayed correctly across different browsers. Acid2 represented a challenge to Microsoft to bring Internet Explorer into compliance with web standards, making it easier to design web pages that work as intended in any web browser.
On October 31, 2005, Safari
2.0.2 became the first browser to pass Acid2. Opera
, Konqueror
, Firefox, and others followed. With the release of Internet Explorer 8
on March 19, 2009, the latest versions of all major desktop web browsers now pass the test. Acid2 was followed by Acid3
.
Acid2 was first proposed by Håkon Wium Lie
, chief technical officer of Opera Software
and creator of the widely used Cascading Style Sheets
web standard. In a March 16, 2005 article on CNET
, Lie expressed dismay that Microsoft Internet Explorer did not properly support web standards and hence was not completely interoperable with other browsers. He announced that Acid2 would be a challenge to Microsoft
to design Internet Explorer 7
, then in development, to achieve a greater degree of standards compliance than previous versions of Internet Explorer. The original Acid1
test had forced browser makers to fix their applications or face embarrassment; Lie hoped that Acid2 would do the same.
Lie and a colleague, Ian Hickson
, had created the first draft of the test in February 2005. Ian Hickson coded the final test in collaboration with the Web Standards Project
and the larger web community. It was officially released on April 13, 2005 and at that time, every web browser failed it spectacularly.
On April 23, 2005, Acid2 was updated to fix a bug that made the mouth appear too close to the nose. After several complaints, the test was again updated in January 2006 to remove a test for unpopular SGML-style comments that were never widely implemented. In browsers that do not implement SGML-style comments, the original test displayed the word "ERROR" on the bottom part of the face.
In March 2008, Ian Hickson released Acid3
as a follow-up to Acid2. While Acid2 primarily tests CSS, Acid3 focuses more on JavaScript
and other "Web 2.0
" technologies.
, describing the test as a "wish list" of features rather than a true test of standards compliance. In December 2007, Microsoft announced that all the changes required to pass Acid2 would be made available in Internet Explorer 8
, but that the changes would not be turned on by default, meaning that IE8 would not actually pass the test. The concern was that switching to a new behavior would cause too many problems in web pages expecting Internet Explorer's old, non-compliant behavior. Then in March 2008 Microsoft released IE8 beta 1 and turned on the changes by default after all. James Pratt, Product Manager for IE8, explained that this decision was made so that "developers can spend more time building features and cool stuff, and less time just trying to tweak their sites across different browsers."
Unfortunately, another unresolved standards compliance issue caused IE8 beta 1 to fail if not all elements of the test were hosted from the same server. In August 2008 Microsoft released IE8 beta 2, which resolved the issue. As of that beta, however, standards mode is not turned on by default for pages loaded in the "Intranet
Zone". This zone is active for pages loaded via UNC paths, named addresses without dots (likehttp://mysite/ ), and sites that bypass the proxy
settings. As such, IE8 will not pass the Acid2 test if loaded in these cases.
published by the World Wide Web Consortium
and the Internet Engineering Task Force
. With the exception of CSS 2.1, all web standards tested were codified before the year 2000. CSS 2.1 was a candidate recommendation at the time of Acid2's release, and is still a candidate recommendation as of 23 April 2009.
Specifically, Acid2 tests:
Because Acid2 is not a comprehensive test, it does not guarantee total conformance to any particular standard. A variant of the Acid2 test that does not test for data URI support is also available from the Web Standards Project.
The following browser settings and user actions invalidate the test:
If rendered correctly, Acid2 will appear as a smiley
face below the text "Hello World!" in the user's browser, with the nose turning blue when the mouse cursor hovers over it. At the time of the test's release every browser failed it, but now a number of applications pass the test:
is based on the same rendering engine as Opera
for personal computer
s, it does not pass the Acid2 test. This is because Opera Mini intentionally reformats web pages to try to make them more suitable for devices with small screens.
Web Standards Project
The Web Standards Project is a group of professional web developers dedicated to disseminating and encouraging the use of the web standards recommended by the World Wide Web Consortium, along with other groups and standards bodies....
to expose web page
Web page
A web page or webpage is a document or information resource that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a monitor or mobile device. This information is usually in HTML or XHTML format, and may provide navigation to other web pages via hypertext...
rendering
Rendering (computer graphics)
Rendering is the process of generating an image from a model , by means of computer programs. A scene file contains objects in a strictly defined language or data structure; it would contain geometry, viewpoint, texture, lighting, and shading information as a description of the virtual scene...
flaws in web browser
Web browser
A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Identifier and may be a web page, image, video, or other piece of content...
s and other applications that render HTML
Layout engine
A web browser engine, , is a software component that takes marked up content and formatting information and displays the formatted content on the screen. It "paints" on the content area of a window, which is displayed on a monitor or a printer...
. Named after the acid test for gold
Acid test (gold)
An acid test is any qualitative chemical or metallurgical assay which uses acid; most commonly, and historically, the use of a strong acid to distinguish gold from base metals. Figuratively, acid test is any definitive test for some attribute, e.g...
, it was developed in the spirit of Acid1
Acid1
Acid1, originally called the Box Acid Test, is a test page for web browsers. It was developed in October 1998 and was important in establishing baseline interoperability between early web browsers, especially for the Cascading Style Sheets 1.0 specification...
, a relatively narrow test of compliance with the Cascading Style Sheets
Cascading Style Sheets
Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...
1.0 (CSS1) standard, and was released on April 13, 2005. As with Acid1, an application passes the test if the way it displays the test page matches a reference image.
Acid2 tests aspects of HTML markup, CSS 2.1 styling, PNG images, and data URIs. The Acid2 test page will be displayed correctly in any application that follows the World Wide Web Consortium
World Wide Web Consortium
The World Wide Web Consortium is the main international standards organization for the World Wide Web .Founded and headed by Tim Berners-Lee, the consortium is made up of member organizations which maintain full-time staff for the purpose of working together in the development of standards for the...
and Internet Engineering Task Force
Internet Engineering Task Force
The Internet Engineering Task Force develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the TCP/IP and Internet protocol suite...
specifications for these technologies. These specifications are known as web standards
Web standards
Web standards is a general term for the formal standards and other technical specifications that define and describe aspects of the World Wide Web. In recent years, the term has been more frequently associated with the trend of endorsing a set of standardized best practices for building web sites,...
because they describe how technologies used on the web are expected to function.
While at the time of Acid2's release no web browser passed the test, Acid2 was designed with Microsoft Internet Explorer particularly in mind. The creators of Acid2 were dismayed that Internet Explorer did not follow web standards, and that because of this, Internet Explorer was prone to display web pages differently from other browsers. When such a discrepancy between browsers is encountered, web developers spend time tweaking
Tweaking
Tweaking refers to fine-tuning or adjusting a complex system, usually an electronic device. Tweaks are any small modifications intended to improve a system....
their web pages in order to make the pages be displayed correctly across different browsers. Acid2 represented a challenge to Microsoft to bring Internet Explorer into compliance with web standards, making it easier to design web pages that work as intended in any web browser.
On October 31, 2005, Safari
Safari (web browser)
Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the...
2.0.2 became the first browser to pass Acid2. Opera
Opera (web browser)
Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...
, Konqueror
Konqueror
Not to be confused with the Conqueror web browser.Konqueror is a web browser and file manager that provides file-viewer functionality for file systems such as local files, files on a remote ftp server and files in a disk image. It is a core part of the KDE desktop environment...
, Firefox, and others followed. With the release of Internet Explorer 8
Internet Explorer 8
Windows Internet Explorer 8 is a web browser developed by Microsoft in the Internet Explorer browser series. The browser was released on March 19, 2009 for Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, and Windows 7. Both 32-bit and 64-bit builds are available...
on March 19, 2009, the latest versions of all major desktop web browsers now pass the test. Acid2 was followed by Acid3
Acid3
Acid3 test is a web test page from the Web Standards Project that checks a web browser's compliance with elements of various web standards, particularly the Document Object Model and JavaScript....
.
History
Håkon Wium Lie
Håkon Wium Lie is a web pioneer, a standards activist, and, , the Chief Technology Officer of Opera Software.He is best known for proposing the concept of Cascading Style Sheets while working with Tim Berners-Lee and Robert Cailliau at CERN in 1994. As an employee at W3C, he developed CSS into a...
, chief technical officer of Opera Software
Opera Software
Opera Software ASA is a Norwegian software company, primarily known for its Opera family of web browsers with over 220 million users worldwide. Opera Software is also involved in promoting Web standards through participation in the W3C. The company has its headquarters in Oslo, Norway and is...
and creator of the widely used Cascading Style Sheets
Cascading Style Sheets
Cascading Style Sheets is a style sheet language used to describe the presentation semantics of a document written in a markup language...
web standard. In a March 16, 2005 article on CNET
CNET
CNET is a tech media website that publishes news articles, blogs, and podcasts on technology and consumer electronics. Originally founded in 1994 by Halsey Minor and Shelby Bonnie, it was the flagship brand of CNET Networks and became a brand of CBS Interactive through CNET Networks' acquisition...
, Lie expressed dismay that Microsoft Internet Explorer did not properly support web standards and hence was not completely interoperable with other browsers. He announced that Acid2 would be a challenge to Microsoft
Microsoft
Microsoft Corporation is an American public multinational corporation headquartered in Redmond, Washington, USA that develops, manufactures, licenses, and supports a wide range of products and services predominantly related to computing through its various product divisions...
to design Internet Explorer 7
Internet Explorer 7
Windows Internet Explorer 7 is a web browser released by Microsoft in October 2006. Internet Explorer 7 is part of a long line of versions of Internet Explorer and was the first major update to the browser in more than 5 years...
, then in development, to achieve a greater degree of standards compliance than previous versions of Internet Explorer. The original Acid1
Acid1
Acid1, originally called the Box Acid Test, is a test page for web browsers. It was developed in October 1998 and was important in establishing baseline interoperability between early web browsers, especially for the Cascading Style Sheets 1.0 specification...
test had forced browser makers to fix their applications or face embarrassment; Lie hoped that Acid2 would do the same.
Lie and a colleague, Ian Hickson
Ian Hickson
Ian 'Hixie' Hickson is the author and maintainer of the Acid2 and Acid3 tests, and the Web Applications 1.0/HTML 5 specification., Sean Michael Kerner, internetnews.com, January 25, 2008 He is known as a proponent of web standards, and has played a crucial role in the development of specifications...
, had created the first draft of the test in February 2005. Ian Hickson coded the final test in collaboration with the Web Standards Project
Web Standards Project
The Web Standards Project is a group of professional web developers dedicated to disseminating and encouraging the use of the web standards recommended by the World Wide Web Consortium, along with other groups and standards bodies....
and the larger web community. It was officially released on April 13, 2005 and at that time, every web browser failed it spectacularly.
On April 23, 2005, Acid2 was updated to fix a bug that made the mouth appear too close to the nose. After several complaints, the test was again updated in January 2006 to remove a test for unpopular SGML-style comments that were never widely implemented. In browsers that do not implement SGML-style comments, the original test displayed the word "ERROR" on the bottom part of the face.
In March 2008, Ian Hickson released Acid3
Acid3
Acid3 test is a web test page from the Web Standards Project that checks a web browser's compliance with elements of various web standards, particularly the Document Object Model and JavaScript....
as a follow-up to Acid2. While Acid2 primarily tests CSS, Acid3 focuses more on JavaScript
JavaScript
JavaScript is a prototype-based scripting language that is dynamic, weakly typed and has first-class functions. It is a multi-paradigm language, supporting object-oriented, imperative, and functional programming styles....
and other "Web 2.0
Web 2.0
The term Web 2.0 is associated with web applications that facilitate participatory information sharing, interoperability, user-centered design, and collaboration on the World Wide Web...
" technologies.
Microsoft's response
In July 2005, Chris Wilson, the Internet Explorer Platform Architect, stated that passing Acid2 was not a priority for Internet Explorer 7Internet Explorer 7
Windows Internet Explorer 7 is a web browser released by Microsoft in October 2006. Internet Explorer 7 is part of a long line of versions of Internet Explorer and was the first major update to the browser in more than 5 years...
, describing the test as a "wish list" of features rather than a true test of standards compliance. In December 2007, Microsoft announced that all the changes required to pass Acid2 would be made available in Internet Explorer 8
Internet Explorer 8
Windows Internet Explorer 8 is a web browser developed by Microsoft in the Internet Explorer browser series. The browser was released on March 19, 2009 for Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, and Windows 7. Both 32-bit and 64-bit builds are available...
, but that the changes would not be turned on by default, meaning that IE8 would not actually pass the test. The concern was that switching to a new behavior would cause too many problems in web pages expecting Internet Explorer's old, non-compliant behavior. Then in March 2008 Microsoft released IE8 beta 1 and turned on the changes by default after all. James Pratt, Product Manager for IE8, explained that this decision was made so that "developers can spend more time building features and cool stuff, and less time just trying to tweak their sites across different browsers."
Unfortunately, another unresolved standards compliance issue caused IE8 beta 1 to fail if not all elements of the test were hosted from the same server. In August 2008 Microsoft released IE8 beta 2, which resolved the issue. As of that beta, however, standards mode is not turned on by default for pages loaded in the "Intranet
Intranet
An intranet is a computer network that uses Internet Protocol technology to securely share any part of an organization's information or network operating system within that organization. The term is used in contrast to internet, a network between organizations, and instead refers to a network...
Zone". This zone is active for pages loaded via UNC paths, named addresses without dots (like
Proxy server
In computer networks, a proxy server is a server that acts as an intermediary for requests from clients seeking resources from other servers. A client connects to the proxy server, requesting some service, such as a file, connection, web page, or other resource available from a different server...
settings. As such, IE8 will not pass the Acid2 test if loaded in these cases.
Overview of standards tested
Acid2 tests a variety of web standardsWeb standards
Web standards is a general term for the formal standards and other technical specifications that define and describe aspects of the World Wide Web. In recent years, the term has been more frequently associated with the trend of endorsing a set of standardized best practices for building web sites,...
published by the World Wide Web Consortium
World Wide Web Consortium
The World Wide Web Consortium is the main international standards organization for the World Wide Web .Founded and headed by Tim Berners-Lee, the consortium is made up of member organizations which maintain full-time staff for the purpose of working together in the development of standards for the...
and the Internet Engineering Task Force
Internet Engineering Task Force
The Internet Engineering Task Force develops and promotes Internet standards, cooperating closely with the W3C and ISO/IEC standards bodies and dealing in particular with standards of the TCP/IP and Internet protocol suite...
. With the exception of CSS 2.1, all web standards tested were codified before the year 2000. CSS 2.1 was a candidate recommendation at the time of Acid2's release, and is still a candidate recommendation as of 23 April 2009.
Specifically, Acid2 tests:
- Alpha transparency in PNG-format images: The eyes of the smiley face use alpha transparency which is part of the 1996 Portable Network Graphics specification. The alpha transparency provides an elegant way to have the eyebrows smoothly blend into the face. This was a significant issue because Internet Explorer 6Internet Explorer 6Internet Explorer 6 is the sixth major revision of Internet Explorer, a web browser developed by Microsoft for Windows operating systems...
, the most widely used web browser at the time Acid2 was released, did not support alpha transparency. This deficiency was rectified in Internet Explorer 7Internet Explorer 7Windows Internet Explorer 7 is a web browser released by Microsoft in October 2006. Internet Explorer 7 is part of a long line of versions of Internet Explorer and was the first major update to the browser in more than 5 years...
, bringing Internet Explorer in line with other web browsers in this regard.
- The object element: The eyes also test support of the HTML object element. The object element has been a part of HTML since HTML 4 was released in 1998, yet by 2005 it still was not completely supported in all web browsers. The creators of Acid2 considered object element support important because it allows for content fallback—if an object fails to load, then the browser can display alternative (generally simpler, more reliable) content in its place.
- data URIs: The actual images that form the eyes are encoded as data URIs. Data URIs allow embedding multimedia directly into web pages rather than being stored as a separate file. Acid2 tests the most common case, where a binaryBinary fileA binary file is a computer file which may contain any type of data, encoded in binary form for computer storage and processing purposes; for example, computer document files containing formatted text...
image is base64Base64Base64 is a group of similar encoding schemes that represent binary data in an ASCII string format by translating it into a radix-64 representation...
-encoded into text and then that encoded text is included in a data URI in the web page. Interestingly, although the IETF published the data URI specification in 1998, they never formally adopted it as a standard. Nonetheless, the HTML 4.01 specification references the data URI scheme and data URI support has now been implemented in most browsers.
- Absolute, relative, and fixed CSS positioning: Absolute positioning means that the web developer specifies the exact X and Y coordinates where an element is to be placed into the page. Relative positioning means that the web developer specifies an X and Y offset from the usual position of the element. Fixed positioning means that the element is placed relative to the browser window, and scrolls with the window rather than with the rest of the page.
- The CSS box model: This feature allows specifying dimensions, padding, borders, and margins, and was the focus of the original Acid1Acid1Acid1, originally called the Box Acid Test, is a test page for web browsers. It was developed in October 1998 and was important in establishing baseline interoperability between early web browsers, especially for the Cascading Style Sheets 1.0 specification...
test. Acid2 not only retests margin support but also tests minimum and maximum heights and widths, features new to CSS 2.0.
- CSS table formatting: This part of CSS allows applying table formatting without traditional HTML table markup.
- CSS generated content: Using CSS generated content, web developers can add decorations and annotations to specified elements without having to add the content to each one individually.
- CSS parsing: A number of illegal CSS statements are present in Acid2 to test error handling. Standards-compliant browsers are expected to handle these errors as the CSS specification directs. This helps ensure cross-browser compatibility by making all browsers treat CSS with the same level of strictness, so that what works in one browser should not cause errors in another.
- Paint order: Acid2 requires that the browser has standard paint order. That is, overlapping elements should be placed or painted on top of each other in the correct order.
- Hovering effects: When the user moves his or her mouse over the smiley face's nose, it turns blue. This is called a hovering effect, and while it has traditionally been used for hyperlinkHyperlinkIn computing, a hyperlink is a reference to data that the reader can directly follow, or that is followed automatically. A hyperlink points to a whole document or to a specific element within a document. Hypertext is text with hyperlinks...
s, it should work on a wide variety of HTML elements.
Because Acid2 is not a comprehensive test, it does not guarantee total conformance to any particular standard. A variant of the Acid2 test that does not test for data URI support is also available from the Web Standards Project.
Passing conditions
A passing score is only considered valid if the browser's default settings were used. Actions such as changing font sizes, zoom level, and applying user stylesheets can break the display of the test. This is expected and is not relevant to a browser's compliance.The following browser settings and user actions invalidate the test:
- Scrolling
- Resizing the browser window
- Zooming in or out
- Disabling images
- Using OperaOpera (web browser)Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...
's Fit to width or Small Screen Rendering modes - Applying custom fonts, colors, styles, etc.
- User JavaScript or GreasemonkeyGreasemonkeyGreasemonkey is a Mozilla Firefox extension that allows users to install scripts that make on-the-fly changes to HTML web page content on the DOMContentLoaded event, which happens immediately after it is loaded in the browser .As Greasemonkey scripts are persistent, the changes made to the web...
scripts - Enabling Internet ExplorerInternet ExplorerWindows Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year...
's "compatibility view"
Compliant applications
  |
If rendered correctly, Acid2 will appear as a smiley
Smiley
A smiley, smiley face, or happy face, is a stylized representation of a smiling human face, commonly occurring in popular culture. It is commonly represented as a yellow circle with two black dots representing eyes and a black arc representing the mouth...
face below the text "Hello World!" in the user's browser, with the nose turning blue when the mouse cursor hovers over it. At the time of the test's release every browser failed it, but now a number of applications pass the test:
Officially released
- Internet ExplorerInternet ExplorerWindows Internet Explorer is a series of graphical web browsers developed by Microsoft and included as part of the Microsoft Windows line of operating systems, starting in 1995. It was first released as part of the add-on package Plus! for Windows 95 that year...
, the web browser that comes with Windows - GeckoGecko (layout engine)Gecko is a free and open source layout engine used in many applications developed by Mozilla Foundation and the Mozilla Corporation , as well as in many other open source software projects....
-based browsers- Mozilla FirefoxMozilla FirefoxMozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers...
, a web browser for Windows, Mac OS X, and Linux - SeaMonkeySeaMonkeySeaMonkey is a free and open source cross-platform Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code...
, an Internet suiteInternet suiteAn Internet suite is an Internet-related software suite. Internet suites usually include a web browser, e-mail client , download manager, HTML editor, and an IRC client....
for Windows, Mac OS X, and Linux - SongbirdSongbird (software)Songbird is a free and open source software audio player and web browser, with a stated mission "to incubate Songbird, the first Web player, to catalyze and champion a diverse, open Media Web."...
, a media player and web browser for Windows, Mac OS X, and Linux - CaminoCaminoCamino is a free, open source, GUI-based Web browser based on Mozilla's Gecko layout engine and specifically designed for the Mac OS X operating system...
, a web browser for Mac OS X - Mozilla ThunderbirdMozilla ThunderbirdMozilla Thunderbird is a free, open source, cross-platform e-mail and news client developed by the Mozilla Foundation. The project strategy is modeled after Mozilla Firefox, a project aimed at creating a web browser...
, an email client for Windows, Mac OS X, and Linux - Firefox for mobile, a web browser for mobile devices
- Miro, an RSS aggregator, BitTorrent client, web browser and media player
- Mozilla SunbirdMozilla SunbirdMozilla Sunbird is a free and open source, cross-platform calendar application that was developed by the Mozilla Foundation, Sun Microsystems and many volunteers...
, a calendar application for Windows, Mac OS X, and Linux - SpicebirdSpicebirdSpicebird is a personal information manager based on Mozilla Thunderbird's code developed by an Indian company called . It is free and open source software....
0.8, a personal information manager for Windows, Mac OS X, and Linux - WebRunnerMozilla PrismMozilla Prism is a product which integrates web applications with the desktop, allowing web applications to be launched from the desktop and configured independently of the default web browser. As of November 2010, Prism is listed as an inactive project at the Mozilla labs website.Prism is based...
(formerly Prism), a web application platform for Windows, Mac OS X, and Linux
- Mozilla Firefox
- WebKitWebKitWebKit is a layout engine designed to allow web browsers to render web pages. WebKit powers Google Chrome and Apple Safari and by October 2011 held over 33% of the browser market share between them. It is also used as the basis for the experimental browser included with the Amazon Kindle ebook...
- and KHTMLKHTMLKHTML is the HTML layout engine developed by the KDE project. It is the engine used by the Konqueror web browser. A forked version of KHTML called WebKit is used by several web browsers, among them Safari and Google Chrome...
-based browsers- SafariSafari (web browser)Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the...
, the web browser included in Mac OS XMac OS XMac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems...
and available for WindowsMicrosoft WindowsMicrosoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal... - Google ChromeGoogle ChromeGoogle Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or...
, a web browser for Windows, Mac OS X, and Linux - KonquerorKonquerorNot to be confused with the Conqueror web browser.Konqueror is a web browser and file manager that provides file-viewer functionality for file systems such as local files, files on a remote ftp server and files in a disk image. It is a core part of the KDE desktop environment...
, a web browser for LinuxLinuxLinux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds... - OmniWebOmniWebOmniWeb is a proprietary Internet web browser developed and marketed by The Omni Group. It is available exclusively for Apple Inc.'s Mac OS X operating system...
, a web browser for Mac OS X - ShiiraShiiraShiira is an open source web browser for the Mac OS X operating system. According to its website, the goal of Shiira was "to create a browser that is better and more useful than Safari". Shiira uses WebKit for rendering and scripting.Shiira Project was led by Makoto Kinoshita. The latest release...
, a web browser for Mac OS X - iCabICabiCab is a web browser for the Macintosh by Alexander Clauss, derived from Crystal Atari Browser for Atari TOS compatible computers. It is the most recently actively developed browser for 68k-based Macintoshes that features tabbed browsing and one of a very few browsers that was still updated in...
, a web browser for Mac OS X - EpiphanyEpiphany (web browser)Epiphany is an open source web browser for the GNOME desktop environment. The browser is a descendant of Galeon, and was created after developer disagreements about Galeon's growing complexity...
, the official GNOMEGNOMEGNOME is a desktop environment and graphical user interface that runs on top of a computer operating system. It is composed entirely of free and open source software...
web browser - Midori, the official XfceXfceXfce is a free software desktop environment for Unix and other Unix-like platforms, such as Linux, Solaris, and BSD – though recent compatibility issues have arisen with regard to BSD Unix platforms...
web browser - The Google EarthGoogle EarthGoogle Earth is a virtual globe, map and geographical information program that was originally called EarthViewer 3D, and was created by Keyhole, Inc, a Central Intelligence Agency funded company acquired by Google in 2004 . It maps the Earth by the superimposition of images obtained from satellite...
integrated web browser
- Safari
- PrestoPresto (layout engine)Presto is the layout engine for later versions of the Opera web browser . After several public betas and technical previews, it was released on January 28, 2003 in Opera 7 for Windows, and as of Opera 11 it is still in use. Presto is dynamic: the page or parts of it can be re-rendered in response...
-based browsers- OperaOpera (web browser)Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...
, a web browser for Windows, Mac OS X, Linux, BSD and Solaris with mobile versions for all mobile phones, tablets and all AppleAppleThe apple is the pomaceous fruit of the apple tree, species Malus domestica in the rose family . It is one of the most widely cultivated tree fruits, and the most widely known of the many members of genus Malus that are used by humans. Apple grow on small, deciduous trees that blossom in the spring...
products like iPadIPadThe iPad is a line of tablet computers designed, developed and marketed by Apple Inc., primarily as a platform for audio-visual media including books, periodicals, movies, music, games, and web content. The iPad was introduced on January 27, 2010 by Apple's then-CEO Steve Jobs. Its size and... - The Internet Channel, a version of the Opera browser for the Nintendo WiiWiiThe Wii is a home video game console released by Nintendo on November 19, 2006. As a seventh-generation console, the Wii primarily competes with Microsoft's Xbox 360 and Sony's PlayStation 3. Nintendo states that its console targets a broader demographic than that of the two others...
game console.
- Opera
- PrincePrince XMLPrince is a proprietary software program that converts XML and HTML documents into PDF files by applying Cascading Style Sheets . It is developed by YesLogic, a small company based in Melbourne, Australia.-History:...
, an XML-to-PDF converter for Windows, Mac OS X, and Linux
In development
- Tkhtml Html Viewer 3TkhtmlTkhtml is an open source layout engine written in C using the Tk widget toolkit. It is used primarily by the Html Viewer 3 minimalist web browser.-History:...
, a web browser for Windows and Linux - GeckoGecko (layout engine)Gecko is a free and open source layout engine used in many applications developed by Mozilla Foundation and the Mozilla Corporation , as well as in many other open source software projects....
-based applications- KazehakaseKazehakaseKazehakase is a web browser for Unix-like operating systems that uses the GTK+ libraries. Kazehakase embeds the Gecko layout engine as well as GTK+ WebKit. However, the author also plans to add the ability to switch between additional different rendering engines...
0.5.4 for Linux and other Unix-likeUnix-likeA Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
operating systems which support GTK+GTK+GTK+ is a cross-platform widget toolkit for creating graphical user interfaces. It is licensed under the terms of the GNU LGPL, allowing both free and proprietary software to use it. It is one of the most popular toolkits for the X Window System, along with Qt.The name GTK+ originates from GTK;...
2.x - K-MeleonK-MeleonK-Meleon is a web browser for the Microsoft Windows platform. Based on the same Gecko layout engine as Mozilla Firefox, K-Meleon uses native Windows application programming interface to create the user interface, instead of using Mozilla's cross-platform XML User Interface Language layer, and as...
, a web browser for Windows
- Kazehakase
- BlackBerry OSBlackBerry OSBlackBerry OS is a proprietary mobile operating system, developed by Research In Motion for its BlackBerry line of smartphone handheld devices...
v5.0.0.230
Non-compliant applications
Even though Opera MiniOpera Mini
Opera Mini is a web browser designed primarily for mobile phones, smartphones and personal digital assistants. Until version 4 it used the Java ME platform, requiring the mobile device to run Java ME applications. From version 5 it is also available as a native application for Android, iOS, Symbian...
is based on the same rendering engine as Opera
Opera (web browser)
Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,...
for personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
s, it does not pass the Acid2 test. This is because Opera Mini intentionally reformats web pages to try to make them more suitable for devices with small screens.
Timeline of passing applications
The following is a list of releases noting significant releases of applications that passed the test. New applications that have passed Acid2 since their first official release are not included in the timeline.| Date | Browser | Availability | Notes |
|---|---|---|---|
| 27 April 2005 | Safari Safari (web browser) Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the... |
private build | |
| 18 May 2005 | iCab ICab iCab is a web browser for the Macintosh by Alexander Clauss, derived from Crystal Atari Browser for Atari TOS compatible computers. It is the most recently actively developed browser for 68k-based Macintoshes that features tabbed browsing and one of a very few browsers that was still updated in... |
private build | This build was made available to registered iCab users on May 20, 2005. |
| 4 June 2005 | Konqueror Konqueror Not to be confused with the Conqueror web browser.Konqueror is a web browser and file manager that provides file-viewer functionality for file systems such as local files, files on a remote ftp server and files in a disk image. It is a core part of the KDE desktop environment... |
private build | |
| 6 June 2005 | iCab ICab iCab is a web browser for the Macintosh by Alexander Clauss, derived from Crystal Atari Browser for Atari TOS compatible computers. It is the most recently actively developed browser for 68k-based Macintoshes that features tabbed browsing and one of a very few browsers that was still updated in... |
public build | Whether this version of iCab truly passes the test or not was questioned because it displays a scrollbar on the test page. The CSS specification states that Acid2 correctly rendered should not have a scrollbar, but also says that "there may exist valid reasons in particular circumstances" to ignore this requirement. |
| 6 June 2005 | Safari Safari (web browser) Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the... |
source code available | WebKit WebKit WebKit is a layout engine designed to allow web browsers to render web pages. WebKit powers Google Chrome and Apple Safari and by October 2011 held over 33% of the browser market share between them. It is also used as the basis for the experimental browser included with the Amazon Kindle ebook... , the underpinnings of Safari, was made open source Open source The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology... on June 6, 2005. When Safari was run with this latest version of WebKit, it passed the Acid2 test. |
| 31 October 2005 | Safari Safari (web browser) Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the... 2.0.2 |
official release | Included in Mac OS X Mac OS X Mac OS X is a series of Unix-based operating systems and graphical user interfaces developed, marketed, and sold by Apple Inc. Since 2002, has been included with all new Macintosh computer systems... 10.4.3. First officially released web browser to pass test. |
| 29 November 2005 | Konqueror Konqueror Not to be confused with the Conqueror web browser.Konqueror is a web browser and file manager that provides file-viewer functionality for file systems such as local files, files on a remote ftp server and files in a disk image. It is a core part of the KDE desktop environment... 3.5 |
official release | First Linux Linux Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds... -compatible browser to pass the test, although it did not hide the scrollbar. |
| 7 December 2005 | Prince Prince XML Prince is a proprietary software program that converts XML and HTML documents into PDF files by applying Cascading Style Sheets . It is developed by YesLogic, a small company based in Melbourne, Australia.-History:... 5.1 |
official release | First non-web browser to pass test. |
| 10 March 2006 | Opera Opera (web browser) Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,... 9 Development build 8249 |
public weekly build | First Microsoft Windows Microsoft Windows Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal... -compatible browser to pass the test and also the first Linux Linux Linux is a Unix-like computer operating system assembled under the model of free and open source software development and distribution. The defining component of any Linux system is the Linux kernel, an operating system kernel first released October 5, 1991 by Linus Torvalds... -compatible browser to pass the test including hiding the scrollbar. A public beta was released on April 20, also successful. |
| 28 March 2006 | Konqueror Konqueror Not to be confused with the Conqueror web browser.Konqueror is a web browser and file manager that provides file-viewer functionality for file systems such as local files, files on a remote ftp server and files in a disk image. It is a core part of the KDE desktop environment... 3.5.2 |
official release | Updated to hide the scrollbar. |
| 11 April 2006 | Mozilla Firefox Mozilla Firefox Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers... |
public nightly build | The "reflow refactoring" nightly builds, whose code was branched Branching (software) Branching, in revision control and software configuration management, is the duplication of an object under revision control so that modifications can happen in parallel along both branches.... from the Gecko Gecko (layout engine) Gecko is a free and open source layout engine used in many applications developed by Mozilla Foundation and the Mozilla Corporation , as well as in many other open source software projects.... 1.9/Firefox 3.0 trunk Trunk (software) In the field of software development, trunk refers to the unnamed branch of a file tree under revision control. The trunk is usually meant to be the base of a project on which development progresses. If developers are working exclusively on the trunk, it always contains the latest cutting-edge... , pass Acid2. |
| 24 May 2006 | Opera Mobile Opera Mobile Opera Mobile is a web browser for smartphones and PDA's developed by the Opera Software company. The first version was released in 2000 for the Psion Series 7 and netBook. Today, it is available for a variety of devices that run on Android, S60, Windows Mobile, Maemo , and MeeGo... for Symbian OS |
private build | First mobile browser to pass test. |
| 20 July 2006 | OmniWeb OmniWeb OmniWeb is a proprietary Internet web browser developed and marketed by The Omni Group. It is available exclusively for Apple Inc.'s Mac OS X operating system... 5.5 beta 1 |
public build | OmniWeb switches its rendering engine to WebKit WebKit WebKit is a layout engine designed to allow web browsers to render web pages. WebKit powers Google Chrome and Apple Safari and by October 2011 held over 33% of the browser market share between them. It is also used as the basis for the experimental browser included with the Amazon Kindle ebook... , the same rendering engine used in Safari Safari (web browser) Safari is a web browser developed by Apple Inc. and included with the Mac OS X and iOS operating systems. First released as a public beta on January 7, 2003 on the company's Mac OS X operating system, it became Apple's default browser beginning with Mac OS X v10.3 "Panther". Safari is also the... which already passed the Acid2 test |
| 20 June 2006 | Opera Opera (web browser) Opera is a web browser and Internet suite developed by Opera Software with over 200 million users worldwide. The browser handles common Internet-related tasks such as displaying web sites, sending and receiving e-mail messages, managing contacts, chatting on IRC, downloading files via BitTorrent,... 9.0 |
official release | |
| 4 July 2006 | Obigo Browser Obigo Browser Obigo Browser is a WEB/WAP browser for mobile phones, smartphones and other Mobile Internet Devices developed by the Obigo company. Obigo browser can run on various mobile platforms such as Windows Mobile, S60 and BREW.-History:... |
private build | Second mobile browser to pass test. |
| 17 August 2006 | iCab ICab iCab is a web browser for the Macintosh by Alexander Clauss, derived from Crystal Atari Browser for Atari TOS compatible computers. It is the most recently actively developed browser for 68k-based Macintoshes that features tabbed browsing and one of a very few browsers that was still updated in... 3.0.3 |
official release | First public release that hides the scrollbar. |
| 6 September 2006 | OmniWeb OmniWeb OmniWeb is a proprietary Internet web browser developed and marketed by The Omni Group. It is available exclusively for Apple Inc.'s Mac OS X operating system... 5.5 |
official release | |
| 8 December 2006 | Mozilla Firefox Mozilla Firefox Mozilla Firefox is a free and open source web browser descended from the Mozilla Application Suite and managed by Mozilla Corporation. , Firefox is the second most widely used browser, with approximately 25% of worldwide usage share of web browsers... , Camino Camino Camino is a free, open source, GUI-based Web browser based on Mozilla's Gecko layout engine and specifically designed for the Mac OS X operating system... , SeaMonkey SeaMonkey SeaMonkey is a free and open source cross-platform Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code... |
public nightly build | Reflow refactoring branch is merged into main Gecko trunk. Firefox, Camino, and SeaMonkey trunk builds now pass Acid2. |
| 5 March 2008 | Internet Explorer 8 Internet Explorer 8 Windows Internet Explorer 8 is a web browser developed by Microsoft in the Internet Explorer browser series. The browser was released on March 19, 2009 for Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, and Windows 7. Both 32-bit and 64-bit builds are available... Beta 1 |
public build | Beta 1 passes the test when hosted at www.webstandards.org, but fails the test when hosted at webstandards.org or acid2.acidtests.org. |
| 17 June 2008 | Mozilla Firefox 3.0 Mozilla Firefox 3 Mozilla Firefox 3.0 is a version of the Firefox web browser released on June 17, 2008 by the Mozilla Corporation.Firefox 3.0 uses version 1.9 of the Gecko layout engine for displaying web pages. This version fixes many bugs, improves standard compliance, and implements many new web APIs compared to... |
official release | |
| 27 August 2008 | Internet Explorer 8 Internet Explorer 8 Windows Internet Explorer 8 is a web browser developed by Microsoft in the Internet Explorer browser series. The browser was released on March 19, 2009 for Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, and Windows 7. Both 32-bit and 64-bit builds are available... Beta 2 |
public build | Beta 2 and later pass the test unless it is hosted from the Intranet Intranet An intranet is a computer network that uses Internet Protocol technology to securely share any part of an organization's information or network operating system within that organization. The term is used in contrast to internet, a network between organizations, and instead refers to a network... Zone. |
| 2 September 2008 | Google Chrome Google Chrome Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or... 0.2 beta |
public build | |
| 14 October 2008 | Flock Flock (web browser) Flock was a web browser that specialized in providing social networking and Web 2.0 facilities built into its user interface.Earlier versions of Flock used the Gecko HTML rendering engine by Mozilla.... 2.0 |
official release | |
| 11 December 2008 | Google Chrome Google Chrome Google Chrome is a web browser developed by Google that uses the WebKit layout engine. It was first released as a beta version for Microsoft Windows on September 2, 2008, and the public stable release was on December 11, 2008. The name is derived from the graphical user interface frame, or... 1.0 |
official release | |
| 19 March 2009 | Internet Explorer 8 Internet Explorer 8 Windows Internet Explorer 8 is a web browser developed by Microsoft in the Internet Explorer browser series. The browser was released on March 19, 2009 for Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, and Windows 7. Both 32-bit and 64-bit builds are available... |
official release | |
| 27 October 2009 | SeaMonkey SeaMonkey SeaMonkey is a free and open source cross-platform Internet suite. It is the continuation of the former Mozilla Application Suite, based on the same source code... 2.0 |
official release | |
| 18 November 2009 | Camino Camino Camino is a free, open source, GUI-based Web browser based on Mozilla's Gecko layout engine and specifically designed for the Mac OS X operating system... 2.0 |
official release | |
| 24 June 2010 | Spicebird Spicebird Spicebird is a personal information manager based on Mozilla Thunderbird's code developed by an Indian company called . It is free and open source software.... 0.8 |
official release |