HTML 5
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It may contain preliminary information that does not reflect the final version of the product.
.html, .htmtext/htmlHTML 5 (HyperText Markup Language 5) is planned to be the fifth major revision of the core language of the World Wide Web, HTML. When HTML 5 is expressed in XML, it is called XHTML 5.
The ideas behind HTML 5, originally referred to as Web Applications 1.0, were pioneered in 2004 by the Web Hypertext Application Technology Working Group (WHATWG); HTML 5 incorporates Web Forms 2.0, another WHATWG standard. The HTML 5 standard was adopted as the starting point of the work of the new HTML working group of the W3C in 2007. The working group has published the First Public Working Draft of the specification on January 22, 2008.[1] The specification is ongoing work, and expected to remain so for many years.[2]
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[edit] New markup
HTML 5 provides a number of new elements and attributes that reflect typical usage on modern Web sites. Some of them are technically similar to <div> and <span> tags, but have a meaning, for example <nav> (website navigation block) and <footer>. Such tags would facilitate indexing by search engines and handling by small-screen devices or voice readers for the visually impaired.[citation needed] Other elements provide new functionality through a standardized interface, such as the <audio> and <video> elements.[3]
Some deprecated elements from HTML 4.01 have been dropped, including purely presentational elements, such as <font> and <center>, whose effects are handled by CSS. There is also a renewed emphasis on the importance of DOM scripting in Web behavior.
[edit] New APIs
In addition to specifying markup, HTML 5 specifies scripting application programming interfaces (APIs).[4] Existing Document Object Model (DOM) interfaces are extended and de facto features documented. There are also new APIs, such as:
[edit] Differences from HTML 4
Here is a cursory list of differences and some specific examples:
section, video, progress, nav, meter, time, aside, canvas New input attributes – dates and times, email, url New attributes – ping, charset, async Global attributes (that can be applied for every element) – id, tabindex, repeat Deprecated elements dropped – center, font, strike[edit] Error handling
An HTML 5 browser should be flexible in handling incorrect syntax, in contrast to XHTML, where such errors must not be ignored. HTML 5 is designed so that old HTML 4 browsers can safely ignore new HTML 5 constructs. In contrast to HTML4, the HTML 5 specification gives detailed rules for lexing and parsing, with the intent that different compliant browsers will produce the same result in the case of incorrect syntax.[5]
[edit] Ogg controversy
HTML 5 introduces new ways of inserting sound and video in webpages with the <audio> and <video> elements. Previously, the specification recommended the use of Ogg formats Vorbis and Theora, but this recommendation was later removed[6] after Apple[7] and Nokia[8] had opposed the move. Opera Software and Mozilla have been advocates for including the Ogg formats into the HTML standard[9][10] and have included native decoding for these formats in their browsers.
On December 11, 2007, mention of the HTML 5 specification was updated replacing the reference to concrete formats with a placeholder:[11]
The removal of the Ogg formats from the spec has been criticized by some Web developers.[12][13] In response to such criticism, WHATWG has cited concerns from influential companies including Nokia and Apple over the Ogg formats still being within patent lifetime and thus vulnerable to unexpected future patent challenges.[14] A follow-up discussion also occurred on the W3C questions & answers blog.
[edit] Background
On October 17, 2007, the W3C encouraged interested people to take part in a "Video on the Web Workshop", held on December 12, 2007 for two days.[15] A number of global companies were involved, submitting position papers.[16] Among them, Nokia's paper states that "a W3C-led standardization of a 'free' codec, or the active endorsement of proprietary technology such as Ogg … by W3C, is, in our opinion, not helpful."[8] Whether Ogg is proprietary is debatable; while the formats are clearly open, they are designed and maintained by an international organization, Xiph.org. Ogg has followed a path similar to many other formats of the Internet age, such as PNG and GZip. While Xiph.org controls and defines the Ogg format specifications and their reference implementations, it does not own any patents and cannot control use of the formats, and the formats are thus not proprietary to Xiph.org.
Maciej Stachowiak — an Apple developer working on WebKit — described the reasons Apple had for opposing the recommendation, in an email message posted to the WHATWG mailing list:[7]
Stachowiak also pointed out that the HTML specifications, traditionally, also failed to specify what referenced formats to use, leaving it to the market to decide.
There is agreement between the vendors that a "baseline" codec of some form is needed: a codec everyone will be able to access.[17] Besides Vorbis and Theora, H.261, H.264, AAC and MP3 were mentioned.[18] The three latter are unacceptable to Opera and Mozilla on both practical and ideological grounds (cf: free software movement). Ogg Theora is unlikely to be accepted by Apple and Nokia, which leaves H.261 and Vorbis. Unlike Theora, Vorbis is already in use by multiple very large corporations,[19] and offers quality comparable to AAC. On December 12, 2007, Xiph.org published their official statement, objecting to some of the arguments against their codecs.[20]
