Version targeting
Encyclopedia
In computing
, version targeting is a technique that allows a group of (presumably knowledgeable) users (including software developer
s) utilise some advanced software features that were introduced in a particular software version while allowing users accustomed to the prior versions still utilise the same software as if the new features were never added to the software. It is a way to ensure backwards compatibility when new software features would otherwise break it.
The term version targeting is mostly applied in the context of Web browser
s, although the concept is not limited to any specific kind of software application. In Web browsers, a DOCTYPE declaration serves a similar purpose.
when it introduced JavaScript
1.6 in Firefox 1.5 and JavaScript 1.7 in Firefox 2.0
: developers willing to use the new scripting engine had to explicitly opt-in.
for use in its Internet Explorer 8
product-in-development, but the idea was later discarded.
The proposal came after the release of Internet Explorer 7
which improved its CSS
2.1 support at the cost of causing some websites that were developed for Internet Explorer 6
to be rendered incorrectly when viewed with the new browser version.
Microsoft contacted the Web Standards Project
and experts on Web standards
and asked for assistance in devising a new DOCTYPE-like technique that could work across browsers and let Web developer
s specify exact browser versions under which their Web sites are known to work correctly, and browsers implementing this form of version targeting would utilise the correct rendering engine
versions to display the site correctly. Members of the WaSP
Microsoft Task Force were involved in the proposal, albeit not every member backed it.
Some commentators suggested that it would be possible to use Internet Explorer 8's support for new DOCTYPEs in order to avoid using its version targeting meta tag.
and for violating the principle of forward-compatible development where progressive enhancement
is preferred.
Version targeting has been criticised for not giving incentives to developers to plan ahead for forward compatibility
.
with Web sites depended on old rendering engines for their functionality.
Computing
Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...
, version targeting is a technique that allows a group of (presumably knowledgeable) users (including software developer
Software developer
A software developer is a person concerned with facets of the software development process. Their work includes researching, designing, developing, and testing software. A software developer may take part in design, computer programming, or software project management...
s) utilise some advanced software features that were introduced in a particular software version while allowing users accustomed to the prior versions still utilise the same software as if the new features were never added to the software. It is a way to ensure backwards compatibility when new software features would otherwise break it.
The term version targeting is mostly applied in the context of 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, although the concept is not limited to any specific kind of software application. In Web browsers, a DOCTYPE declaration serves a similar purpose.
In Mozilla Firefox
Version targeting has been used in Mozilla FirefoxMozilla 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...
when it introduced 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....
1.6 in Firefox 1.5 and JavaScript 1.7 in Firefox 2.0
Mozilla Firefox 2
Mozilla Firefox 2 was a version of Firefox, a web browser released on October 24, 2006 by the Mozilla Corporation.Firefox 2 uses version 1.8 of the Gecko layout engine for displaying web pages...
: developers willing to use the new scripting engine had to explicitly opt-in.
Use in Internet Explorer
Version targeting was proposed by MicrosoftMicrosoft
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...
for use in its 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...
product-in-development, but the idea was later discarded.
The proposal came after the release of 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...
which improved its CSS
CSS
-Computing:*Cascading Style Sheets, a language used to describe the style of document presentations in web development*Central Structure Store in the PHIGS 3D API*Closed source software, software that is not distributed with source code...
2.1 support at the cost of causing some websites that were developed for Internet Explorer 6
Internet Explorer 6
Internet Explorer 6 is the sixth major revision of Internet Explorer, a web browser developed by Microsoft for Windows operating systems...
to be rendered incorrectly when viewed with the new browser version.
Microsoft contacted 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 experts on 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,...
and asked for assistance in devising a new DOCTYPE-like technique that could work across browsers and let Web developer
Web developer
A web developer is a software developer or software engineer who specializes in, or is specifically engaged in, the development of World Wide Web applications, or distributed network applications that are run over HTTP from a web server to a web browser....
s specify exact browser versions under which their Web sites are known to work correctly, and browsers implementing this form of version targeting would utilise the correct rendering engine
Rendering engine
Rendering engine may refer to:*Game engine, a software system designed for the creation and development of video games*Ray tracing , a technique for generating an image by tracing simulated rays of light...
versions to display the site correctly. Members of the WaSP
WAsP
WAsP is a PC program for predicting wind climates, wind resources, and power productions from wind turbines and wind farms. The predictions are based on wind data measured at stations in the same region. The program includes a complex terrain flow model, a roughness change model, and a model for...
Microsoft Task Force were involved in the proposal, albeit not every member backed it.
Some commentators suggested that it would be possible to use Internet Explorer 8's support for new DOCTYPEs in order to avoid using its version targeting meta tag.
Criticism
The concept of version targeting, especially as proposed by Microsoft, has been criticised for being a new form of browser sniffingBrowser sniffing
Browser sniffing is a technique used in websites and web applications in order to determine the web browser a visitor is using, and to serve browser-appropriate content to the visitor. This practice is sometimes utilized to circumvent incompatibilities between browsers in areas such as the...
and for violating the principle of forward-compatible development where progressive enhancement
Progressive enhancement
Progressive enhancement is a strategy for web design that emphasizes accessibility, semantic HTML markup, and external stylesheet and scripting technologies...
is preferred.
Version targeting has been criticised for not giving incentives to developers to plan ahead for forward compatibility
Forward compatibility
Forward compatibility or upward compatibility is a compatibility concept for systems design, as e.g. backward compatibility. Forward compatibility aims at the ability of a design to gracefully accept input intended for later versions of itself...
.
Positive reception
Version targeting has been welcomed by some people as a means to enable browsers adopt Web standards without breaking compatibilityCompatibility
Compatibility may refer to:* Astrological compatibility* Compatibilism – a philosophical position* Compatibility * Compatibility * Compatibility * Electromagnetic compatibility* Interpersonal compatibility-Computing:...
with Web sites depended on old rendering engines for their functionality.