The following tables compare support for different font formats and support for CSS3 font resources for a number of layout engines. Web fonts were initially defined (but later dropped) from CSS2, then added into CSS3. The specification is supported by an increasing number of web browsers.

Support for CSS font resources

CSS3 specified a mechanism for downloading and displaying fonts within a web page. This table compare support for that mechanism. Note that EOT font download does not bring in the entire OpenType font and therefore, the most prominent feature of Open Type, ligature support, does not come with EOT. Trident supports only EOT. EOT is not sufficient for smartfonts that rely on ligatures.

		Trident Trident (layout engine) Trident is the name of the layout engine for the Microsoft Windows version of Internet Explorer.It was first introduced with the release of Internet Explorer version 4.0 in October 1997; it has been steadily upgraded and remains in use today...	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....	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...	Presto Presto (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...
Grammar and rules
CSS3	@font-face
Descriptors
CSS3	font-family		rowspan="4"	rowspan="4"	rowspan="4"
	src
	font-style	rowspan="2"
	font-weight
	font-stretch	rowspan="2"			rowspan="2"
	unicode-range
	font-variant	rowspan="2"		rowspan="2"	rowspan="2"
	font-feature-settings

Support in HTML and XML documents

This table compares support for font formats applied with the @font-face rule in HTML

HTML

HyperText Markup Language is the predominant markup language for web pages. HTML elements are the basic building-blocks of webpages....

 and XML

XML

Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....

 documents.

Format	Trident Trident (layout engine) Trident is the name of the layout engine for the Microsoft Windows version of Internet Explorer.It was first introduced with the release of Internet Explorer version 4.0 in October 1997; it has been steadily upgraded and remains in use today...	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....	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...	Presto Presto (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...
Embedded OpenType (EOT) Embedded OpenType Embedded OpenType fonts are a compact form of OpenType fonts designed by Microsoft for use as embedded fonts on web pages. These files usually use the extension ".eot"....
TrueType (TTF) TrueType TrueType is an outline font standard originally developed by Apple Computer in the late 1980s as a competitor to Adobe's Type 1 fonts used in PostScript...	rowspan="2"	rowspan="2"	rowspan="3"	rowspan="3"
OpenType (OTF) OpenType OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior...
Scalable Vector Graphics (SVG) Scalable Vector Graphics Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic . The SVG specification is an open standard that has been under development by the World Wide Web Consortium since 1999.SVG images and their...
Web Open Font Format (WOFF) Web Open Font Format The Web Open Font Format is a font format for use in web pages. It was developed during 2009 and is in the process of being standardized as a recommendation by the World Wide Web Consortium Web Fonts Working Group....

Support in SVG documents

This table compares support for font formats applied with the @font-face rule in SVG

Scalable Vector Graphics

Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic . The SVG specification is an open standard that has been under development by the World Wide Web Consortium since 1999.SVG images and their...

 documents.

Format	Trident Trident (layout engine) Trident is the name of the layout engine for the Microsoft Windows version of Internet Explorer.It was first introduced with the release of Internet Explorer version 4.0 in October 1997; it has been steadily upgraded and remains in use today...	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....	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...	Presto Presto (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...
Embedded OpenType (EOT) Embedded OpenType Embedded OpenType fonts are a compact form of OpenType fonts designed by Microsoft for use as embedded fonts on web pages. These files usually use the extension ".eot"....	rowspan="5"
TrueType (TTF) TrueType TrueType is an outline font standard originally developed by Apple Computer in the late 1980s as a competitor to Adobe's Type 1 fonts used in PostScript...			rowspan="3"
OpenType (OTF) OpenType OpenType is a format for scalable computer fonts. It was built on its predecessor TrueType, retaining TrueType's basic structure and adding many intricate data structures for prescribing typographic behavior...
Scalable Vector Graphics (SVG) Scalable Vector Graphics Scalable Vector Graphics is a family of specifications of an XML-based file format for describing two-dimensional vector graphics, both static and dynamic . The SVG specification is an open standard that has been under development by the World Wide Web Consortium since 1999.SVG images and their...
Web Open Font Format (WOFF) Web Open Font Format The Web Open Font Format is a font format for use in web pages. It was developed during 2009 and is in the process of being standardized as a recommendation by the World Wide Web Consortium Web Fonts Working Group....

Smart font features support

Format	Trident Trident (layout engine) Trident is the name of the layout engine for the Microsoft Windows version of Internet Explorer.It was first introduced with the release of Internet Explorer version 4.0 in October 1997; it has been steadily upgraded and remains in use today...	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....	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...	Presto Presto (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...
OpenType liga ligatures	rowspan="2"	rowspan="3"	On Safari, ligatures may be switched on with the CSS setting text-rendering, but then, they are used indiscriminately even when letter-spacing is increased (see Fraktur letterspacing); on Google Chrome, ligatures do not work.	rowspan="2"
OpenType rlig ligatures
ZWNJ Zero-width non-joiner The zero-width non-joiner is a non-printing character used in the computerization of writing systems that make use of ligatures. When placed between two characters that would otherwise be connected into a ligature, a ZWNJ causes them to be printed in their final and initial forms, respectively...  and ZWJ Zero-width joiner The zero-width joiner is a non-printing character used in the computerized typesetting of some complex scripts, such as the Arabic script or any of the Indic scripts. When placed between two characters that would otherwise not be connected, a ZWJ causes them to be printed in their connected... (Unicode characters used for ligature control)			When letter-spacing is increased, these characters are spacing.