Legend

Supported
Not supported
Partially supported
Support unknown

WYSIWYG editable elements (contenteditable attribute)

- Working Draft

Method of making any HTML element editable

Resources:
Demo page
WHATWG blog post
Blog post on usage problems
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

PNG alpha transparency

- Candidate Recommendation

Semi-transparent areas in PNG files

Resources:
W3 Test files
Workaround for IE6
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS position:fixed

- Candidate Recommendation

Method of keeping an element in a fixed location regardless of scroll position

Resources:
Workaround for IE6
Workaround for Mobile Safari
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Also does not work on Mobile Safari 3.1

CSS 2.1 selectors

- Candidate Recommendation

Allows more accurate element selecting, using >, +, [attr], :first-child, etc.

Resources:
Detailed support information
Examples of advanced selectors
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS table display

- Candidate Recommendation

Method of displaying elements an tables, rows, and cells

Resources:
Detailed article on usage
Blog post on usage
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS generated content ( :before and :after )

- Candidate Recommendation

Method of displaying text or images before or after elements

Resources:
Guide on usage
Examples of different types of generated content
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS3 Box-sizing

- Candidate Recommendation

Method of specifying whether or not an element's borders, padding and margin should be including in size units

Resources:
MDC Article
Information page
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Data URLs

- IETF standard

Method of embedding images and other files in webpages as a string of text.

Resources:
Information on usage
Image encoder
Wikipedia
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Support in Internet Explorer 8b2 is limited to images and linked resources like CSS files, not HTML files. Max URI length is 32KB.

querySelector/querySelectorAll (Selectors API)

- Candidate Recommendation

Method of accessing DOM elements using CSS selectors

Resources:
Selectors test including querySelectorAll
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Only works for the CSS selectors available. Thus the IE8 implementation is limited to the CSS 2.1 selectors

Font linking (@font-face)

- Working Draft

Method of displaying fonts downloaded from websites

Resources:
News and information site
Font demo
Wikipedia
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Trident (Internet Explorer) only supports EOT fonts. Opera does not support the font when 'format("opentype")' is used, although it does otherwise appear to support OTF fonts

Cross-document messaging

- Working Draft

Method of sending information from pages on different domains to each other (using postMessage)

Resources:
Demo
MDC Article
Simple demo
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

getElementsByClassName

- Working Draft

Method of accessing DOM elements by class name

Resources:
Test page
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

New, stylable HTML5 elements

- Working Draft

HTML5 offers some new elements, primarily for semantic purposes. The "stylable" part refers to the ability to use CSS on these elements

Resources:
Workaround for IE
Alternate workaround
Examples of usage
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: In Firefox 2 and older, unknown elements are self-closing (like a br or img element) when serving the page as text/html. HTML 5 Elements in pages served as XHTML work as expected

CSS3 Colors

- Candidate Recommendation

Method of describing colors using HSL, as well as allowing alpha-transparency

Resources:
Dev.Opera article
Guide to HSL & HSLA
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Incomplete support by older Opera versions refers to the lack of support for RGBA/HSLA.

SVG (basic support)

- Recommendation

Method of displaying basic Vector Graphics features using the embed or object elements

Resources:
Wikipedia
Sample files
SVG showcase site
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Canvas (basic support)

- Working Draft

Method of generating dynamic graphics using JavaScript

Resources:
Tutorial by Mozilla
Showcase site
Animation kit
Another tutorial
Implementation for Internet Explorer
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Client-side storing of name/value pairs (Web Storage)

- Working Draft

Method of storing data locally like cookies, but for larger amounts of data (sessionStorage and localStorage, used to fall under HTML5).

Resources:
Gecko reference
Support library
Simple demo
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

XHTML served as application/xhtml+xml

- Recommendation

A strict form of HTML, and allows embedding of other XML languages

Resources:
Wikipedia
Examples compared to text/html pages
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: The XHTML syntax is very close to HTML, and thus is almost always served as text/html on the web.

CSS3 selectors

- Proposed Recommendation

Advanced element selection

Resources:
Detailed support information
W3C Test suite
Automated CSS3 selector test
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Audio element

- Working Draft

Method of playing sound on webpages (without requiring a plug-in)

Resources:
HTML5 Doctor article
Detailed article on video/audio elements
Demos of audio player that uses <audio>
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Partial support in Opera refers to support for the HTML5 audio object, not the element.

CSS3 Media Queries

- Candidate Recommendation

Method of applying styles based on media information. Includes things like page and device dimensions

Resources:
IE demo page with information
Demo page for page width
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Incomplete support by webkit refers to only acknowledging different media rules on page reload

CSS3 Rounded corners (border-radius)

- Candidate Recommendation

Method of making the border corners round

Resources:
Border-radius CSS Generator
Detailed compliance table
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Incomplete support refers to non-antialiased corners

Video element

- Working Draft

Method of playing videos on webpages (without requiring a plug-in)

Resources:
Detailed article on video/audio elements
WebM format information
Video for Everybody
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Safari and Internet Explorer do not support Ogg/Theora/Vorbis, while Opera and Firefox don't support MPEG-4/H.264/AAC. Chrome supports both. Upcoming versions of Firefox, Chrome and Opera will support the WebM/VP8 format. IE9 will support it if the user has the codec installed.

CSS3 Text-shadow

- Working Draft

Method of displaying shadow or blur effect to text

Resources:
Mozilla hacks article
Live editor
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: This spec used to be Candidate Recommendation, but that version has been made obsolete. Incomplete support by webkit refers to the lack of support for multiple shadows.

CSS3 Box-shadow

- Working Draft

Method of displaying shadow or blur effect to elements

Resources:
MDC article
Live editor
Demo of various effects
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Partial support in IE9 refers to behavior inconsistent with other browsers

Accessibility for AJAX and other web features (WAI-ARIA)

- Working Draft

Method of providing ways for people with disabilities to use dynamic web content and web applications

Resources:
Information page
Support chart
Tutorial
Wikipedia
ALA Article
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS3 Multiple backgrounds

- Candidate Recommendation

Method of using multiple images as a background

Resources:
Example page
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS3 Border images

- Candidate Recommendation

Method of using images for borders

Resources:
Information page with fallback script
Example page
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS3 Transforms

- Working Draft

Method of transforming an element including rotating, scaling, etc.

Resources:
Live editor
MDC article
Workaround script for IE
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Current implementations may change significantly from final specification, since W3C adoption is quite recent. The scale transform can be emulated in IE using Microsoft's "zoom" extension, others are (not easily) possible using the MS Matrix filter

Text API for Canvas

- Working Draft

Method of displaying text on Canvas elements

Resources:
Examples by Mozilla
Example chart
Support library
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

CSS3 Background-image options

- Working Draft

New properties to affect to background images, including background-clip, background-origin and background-size

Resources:
Detailed compatibility tables and demos
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Opera 9.5 and 10.1 support background-size, but no other features

SVG in CSS backgrounds

- Candidate Recommendation

Method of using SVG images as CSS backgrounds

Resources:
Test page
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Incomplete support by webkit refers to limitations on the conditions (see test page for examples). Support in IE9 not yet available, but currently planned.

Offline web applications

- Working Draft

Method of selecting web page files to be cached, thus allowing them to work offline on subsequent visits to the page

Resources:
Sitepoint tutorial
Offline app demo
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Also supported in Mobile Safari 3.1+ Support in < Chrome 4.0 uses the auto-included Gears plug-in. Functions are similar, but not the same.

Drag and Drop

- Working Draft

Method of easily dragging and drop elements on a page

Resources:
HTML5 Doctor article
Demo with text blocks
Demo with link blocks
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Independent JavaScript threading (Web Workers)

- Working Draft

Method of running scripts in the background, isolated from the web page

Resources:
MDC article
Web Worker demo
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Support in Chrome uses the auto-included Gears plug-in. Functions are similar, but not the same.

CSS3 Transitions

- Working Draft

Simple method of animating certain properties of an element

Resources:
Article on usage
Webkit blog post
Examples on timing functions
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Current implementations may change significantly from final specification, since W3C adoption is quite recent.

SVG effects for HTML elements

- Working Draft

Method of using SVG transforms, filters, etc on HTML elements using either CSS (unofficial) or the <foreignObject> element

Resources:
Blog post with foreignObject demos
MDC Reference page
SVG CSS Effects draft
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Partial support refers to lack of filter support or buggy result from effects. CSS method is a proposal by Mozilla, being considered for W3C standardization (stats, however, are considered based on the foreignObject support).

SVG SMIL animation

- Recommendation

Method of using animation elements to animate SVG images

Resources:
Example files
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Gecko support expected for Gecko 1.9.3

Cross-Origin Resource Sharing

- Working Draft

Method of performing XMLHttpRequests across domains

Resources:
Mozilla Hacks blog post
Alternative implementation by IE8
Demo and script with cross-browser support
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Supported somewhat in IE8 using the XDomainRequest object

CSS3 Multiple column layout

- Candidate Recommendation

Method of flowing information in multiple columns

Resources:
Demo page
Introduction page
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

SVG fonts

- Recommendation

Method of using fonts defined as SVG shapes

Resources:
Information page
Blog post on usage for iPad
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Flexible Box Layout Module

- Working Draft

Method of positioning elements in horizontal or vertical stacks.

Resources:
Introduction with demos
Another article
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: While only recently a W3C specification, this system has been in use for some time by Mozilla and Apple for interface purposes.

Geolocation

- Working Draft

Method of informing a website of the user's geographical location

Resources:
Demo
MDC Article
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Support in Chrome uses the auto-included Gears plug-in. Functions are similar, but not the same.

Client-side SQL Database Storage (Web SQL Database)

- Working Draft

Method of storing data locally, allows Sqlite database queries for access and manipulation

Resources:
HTML5 Doctor article
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: The Web database specification is currently "on hold" as it is waiting for a non-Sqlite implementation. Firefox and IE are unlikely to support this and offer IndexedDB support instead.

HTML5 form features (Web Forms 2.0)

- Working Draft

Expanded form options, including things like date pickers, sliders and validation

Resources:
HTML5 inputs and attribute support page
Cross-browser JS implementation (based on original spec)
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Webkit browsers support "search", "meter" and multiple file uploads. Older Opera implementations are based on the original WHATWG specification. Some changes have been made in HTML5

SVG filters

- Recommendation

Method of using photoshop-like effects on SVG shapes

Resources:
Advanced filter effects
W3C example
Webkit bug report
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Ruby annotation elements

- Working Draft

Method of adding pronunciation or other annotations (primarily used in East Asian typography)

Resources:
HTML5 Doctor article
Add-on for support in Firefox
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Browsers without native support can still simulate support using CSS. Partial support refers to only supporting basic ruby, may still be missing writing-mode, Complex ruby and CSS3 Ruby

CSS3 Animation

- Working Draft

Complex method of animating certain properties of an element

Resources:
Blog post on usage
Webkit blog post
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Current implementations may change significantly from final specification, since W3C adoption is quite recent.

Web Sockets

- Working Draft

Bidirectional communication technology for web apps

Resources:
WebSockets information
Chromium blog post
Wikipedia
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Server-sent DOM events

- Working Draft

Method of continuously sending data from a server to the browser, rather than repeatedly requesting it (EventSource interface, used to fall under HTML5)

Resources:
Opera blog post w/info
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Opera implementation is based on the original WHATWG specification, using the <event-source> HTML element. Much has changed in the specification since then, and no element is actually used.

MathML

- Recommendation

An XML language that allows mathematical formulas and notations to be written on web pages.

Resources:
Wikipedia
MathML basics (Mozilla)
MathML Opera Torture Tests
Info on Opera's MathML support
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Opera's support is limited to a CSS profile of MathML

3D Canvas graphics / WebGL

- Working Draft

Method of generating dynamic 3D graphics using JavaScript, accelerated through hardware

Resources:
Instructions on enabling WebGL
Tutorial
Firefox blog post
Webkit blog post
Opera blog post (not WebGL)
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: WebGL is a new standard that is still being developed. It is currently disabled by default in all browsers with support. Note also that it is part of the Khronos Group, not the W3C

Client-side file opening and handling (File API)

- Working Draft

Method of allowing users to select one or more files from their hard drive for a web page to manipulate

Resources:
MDC article
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Support is planned for Chrome 6, but not yet implemented

Inline SVG in HTML5

- Working Draft

Method of using SVG tags directly in HTML documents. Requires HTML5 parser.

Resources:
Mozilla Hacks blog post
Demo of multi-browser support using the SVGWeb library
Test suite
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Currently only works in Firefox 3.6 by enabling the HTML5 parser in about:config (not recommended)

CSS3 3D Transforms

- Working Draft

Method of transforming an element in the third dimension

Resources:
Webkit blog post
Demo page
Cubic panorama demo (Mobile Safari only)
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Only supported in the Mac/mobile versions of Safari. Current implementations may change significantly from final specification, since W3C adoption is quite recent.

Client-side Database Storage (Indexed Database API, previously WebSimpleDB API)

- Working Draft

Method of storing data locally, allows indexed database queries

Resources:
Mozilla Hacks article
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Support planned for Chrome 7, but not yet implemented

Length calculations in CSS (calc())

- Working Draft

Method of allowing calculated values for length units, i.e. width: calc(100%-3em)

Resources:
Mozilla bug report
Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.03.03.23.010.1
Previous version7.03.54.04.010.5
Current8.03.65.05.010.6
Near Future (2010)4.06.0
Future (2011 or later)9.05.*7.010.7

Note: Current Firefox implementation only works on a few properties and uses -moz-calc()

Summary

Calculation of support of currently displayed feature lists

Internet ExplorerFirefoxSafariChromeOpera
Two versions back6.0: 4%3.0: 41%3.2: 56%3.0: 75%10.1: 50%
Previous version7.0: 11%3.5: 68%4.0: 76%4.0: 80%10.5: 70%
Current8.0: 26%3.6: 75%5.0: 86%5.0: 85%10.6: 75%
Near Future (2010)8.0: 26%4.0: 89%5.0: 86%6.0: 89%10.6: 75%
Future (2011 or later)9.0: 59%4.0: 89%5.*: 87%7.0: 90%10.7: 77%

*Note that "Not ready" does not mean you can't start using it, it just means it won't work in all current selected browsers. Change the options to hide browsers you do not need to support.

FAQ

Which features do you choose to add to this list?

I use the following criteria:

  1. Useful to web designers/developers
  2. Likely to be eventually implemented by the majority of browsers
  3. Currently implemented by at least one browser
  4. Currently lacking at least one implementation

Where do you get your information?

Most information comes directly from the latest developer/preview/nightly builds as seen in this list:

Why include Chrome and Safari separately, since they both use Webkit?

Each browser may choose to include different features of webkit in their final versions, so they are not always the same.

What's the point in having the conclusion if it will always be "not ready" with an implementation missing?

The conclusion will change when hiding certain browsers/eras, which is why it's there.

How do you decide which version belongs in which "era"?

The "far past" is based roughly on the oldest version of a browser still in use. See for example YUI's graded browser support chart

The "future" eras are trickier, since it's not always obvious when a browser will be released. But in most cases you can make a pretty good guess.

When is a feature considered "supported"?

When its primary purpose is largely fulfilled. It does not mean it's 100% supported, just that it's usable in most cases.

Is there an intentional bias against Internet Explorer?

I will admit that part of my reason to create this page was to highlight how many features could be used already if it weren't for IE holding us back. However, I have tried to keep things as balanced as possible and no intentional bias should exist.

Then why are there more unofficial features by other browsers? Where's IE's filter, CSS behaviors, etc?

As mentioned as a criteria, it needs to be likely for most if not all browsers to support a feature, ideally through standardization. Many IE-specific features were never proposed to the W3C/WhatWG, and other browsers have shown little to no interest in adopting them.

If it turns out that other browser-specific features show little chance of reaching further adoption, I will remove them as well.

How often is this page updated?

I try to keep it as current as possible, with new information being usually being processed within a few days. Follow the feed if you'd like keep up with all the changes made.

By @Fyrd