What is HTML5?

Source: Internet
Author: User
Tags error handling exception handling line web new features versions

HTML 5 is the most significant leap in web development standards in nearly a decade. Unlike previous versions, HTML 5 is not just for Web content, its new mission is to bring the Web into a sophisticated application platform, where video, audio, graphics, animations, and interactions with computers are standardized on the HTML 5 platform.

What is HTML5?

HTML5 will become the new standard for HTML, XHTML, and HTML DOM.

The last version of HTML was born in 1999. Since then, the Web world has undergone great changes.

HTML5 is still in perfect. However, most modern browsers already have some HTML5 support.

How did the HTML5 start?

HTML5 is the result of cooperation between the WHATWG and the consortium.

Note 1:W3C refers to the World Wide Web Consortium, www Federation.

Note 2:WHATWG refers to the Web Hypertext application Technology Working Group.

WHATWG is dedicated to Web forms and applications, while the consortium focuses on XHTML 2.0. In 2006, the two sides decided to collaborate to create a new version of HTML.

Some of the rules established for HTML5:

The new features should be based on HTML, CSS, DOM, and JavaScript.

Reduce the need for external plug-ins (such as Flash)

More excellent error handling

More tokens to replace scripts

HTML5 should be independent of equipment

Development process should be transparent to the public

The predecessor of the draft HTML5 is Web Applications 1.0. Was proposed in 2004 by WHATWG, was accepted in 2007 by the consortium, and set up a new HTML team. On January 22, 2008, the first official draft was published and is expected to be formally recommended to the public in September 2010. WHATWG said the code is currently under way, and it still has to be done for years.

New tag

HTML5 provides some new elements and attributes, such as (site navigation block) and. This tag will facilitate indexing of search engines and better help with small-screen devices and visually impaired people, as well as new features, such as and tags, for other browsing elements.

Some obsolete HTML4 tags will be canceled. This includes a pure display of the effect of the tag, such as and

, they have been replaced by CSS.

New features

Some of the interesting new features in HTML5:

The canvas element for painting

Video and audio elements for media playback

Better support for local offline storage

New special content elements, such as article, footer, header, nav, section

New form controls, such as Calendar, date, time, email, url, search

Browser support

The latest versions of Safari, Chrome, Firefox, and Opera support certain HTML5 features. Internet Explorer 9 will support certain HTML5 features.

HTML5: Changes in labels

HTML5 absorbs some of the recommendations of XHTML 2, including the ability to improve the structure of the document, such as the use of new HTML tag Headers, footer, dialog, aside, fugure, etc., which allows content creators to create documents more semantically, before developers Some occasions are the use of Div.

HTML5 also contains some effort to separate content from presentation, and developers may be surprised that the B and I tags still exist, but their meaning has been different from before, and the meaning of these tags is just to identify a piece of text, not to set the bold or italic sample for them. U,font,center,strike These labels are completely removed.

The new standard applies to a number of new form input objects, including dates, url,email addresses, and other objects that increase support for non-la-G characters. HTML5 also introduces micro-data, a method that uses machine-identifiable tags to annotate content, making semantic Web processing simpler. In general, these structural improvements enable content creators to create cleaner, more manageable web pages that are friendlier to search engines and to read-screen software.

New application Interface (API)

In addition to the original DOM interface, HTML5 has added more APIs, such as:

1. Canvas label for instant 2D drawing

2. Timed Media playback

3. Offline database storage

4. Document editing

5. Drag and Drop control

6. Browsing History Management

The difference from HTML 4

New parsing sequence new elements: section, video, progress, nav, meter, time, aside, canvasinput elements of the new attributes: dates and times, emails, URLs. New Common properties: Ping, CharSet, async Global properties: ID, TabIndex, repeat. remove element: Center, font, strike.

HTML 5 has two main features:

First, the performance of Web pages is enhanced. In addition to depicting two-dimensional graphics, a label is prepared for playing video and audio.

Secondly, the functions of Web applications such as local database are appended.

Exception handling

HTML5 (text/html) browsers will be more flexible in handling error syntax. HTML5 is designed to ensure that old browsers can safely ignore new HTML5 code. Compared with HTML4.01, HTML5 gives detailed rules for parsing, trying to make it possible for different browsers to return the same results even when grammatical errors occur.

HTML 5 is changing the Web

HTML5 is the most dramatic leap in WEB standards in nearly a decade. Unlike previous versions, HTML 5 is not just for Web content, its mission is to bring the Web into a sophisticated application platform where video, audio, graphics, animations, and interactions with computers are standardized. Although the implementation of HTML 5 still has a long way to go, HTML 5 is changing the Web.

The most recent update to HTML was HTML 4.01, published in December 1999. Since then, a lot has happened. The initial browser war was over, Netscape was destroyed, and IE5 as a winner later developed to IE6, IE7. Mozilla Firefox was born from the ashes of Netscape and leaped second. Apple and Google have each launched their own browsers, while Xiaojiabiyu Opera is still buzzing with hindering and driving the WEB standard for its own life. We even have a real Web experience on our phones and consoles, thanks to Opera,iphone and Google's Android.

All this, however, has only made the WEB standard movement even more confusing, with HTML 5 and other standards shelved and, as a result, HTML 5 has always been a draft.

As a result, some companies banded together to set up an organization called the Web Hypertext Application Technology Working Group (Web Hypertext Technology Workgroup-WHATWG), which will pick up HTML 5 again. The group is independent of the consortium, with members from Mozilla, Khtml/webkit, Google,apple,opera and Microsoft. Although the HTML 5 draft will not be approved in the short term, HTML 5 can finally be extended.

What will HTML 5 bring? Here are the most exciting parts of the draft HTML 5:

New, more reasonable tag, multimedia objects will no longer be all bound in the object or embed tag, but the video has a video tag, audio has audio tag. Local database. This feature will embed a local SQL database to speed up interactive search, caching, and indexing functions. Also, those offline WEB programs will benefit. No plug-ins are required for rich animations. The Canvas object will give the browser the ability to draw vector graphs directly above, which means that we can leave Flash and Silverlight and display graphics or animations directly in the browser. Some of the latest browsers, in addition to IE, have started to support Canvas. The real program in the browser. will provide the ability of the API to implement the editing, drag and drop, and various graphical user interfaces within the browser. The content modifier Tag will be removed while using CSS. In theory, HTML 5 is the soil that nurtures the new WEB standards, allowing various ideas to be shared among his organizers, but HTML 5 is still in the experimental phase.

"HTML 5 is a concept that is high on the scale, both as an experimental field in WHATWG and as a standard way for the consortium," says Mike Shaver, Mozilla's VP of Technology.

Shaver that Mozilla's interests coincide with the WHATWG experiment, and Mozilla is very active in the HTML 5 workgroup, and we experimented with some of the early rules and presented the results to the consortium.

Over the past few years, Mozilla has launched several forward-looking projects with various new standards, including Prism, a system for off-line Web applications, and a Weave, a data storage framework.

Shaver said that the HTML 5 movement began with impatience with the consortium, and that much of the progress in WEB standards stagnated because the consortium shifted its focus from HTML to XML.

Many new technologies based on XML architecture are designed to replace Html,shaver said, this is not a correct way, people should not be like heixiazi break the corn to throw away side.

New experiments with HTML 5 have been reinforced in Firefox as well as in Webkit Safari and Chrome browsers, but there are still many problems.

Chrome's developer, Darin Fisher, said Chrome had to face several problems when it was still in its infancy, even though the latest webkit,html 5 local database feature was not implemented in the initial version of Chrome. Because Chrome's sandbox mechanism conflicts with the Webkit database functionality.

And because Chrome is a secret development, chrome developers are also not involved in Webkit development.

If we want to keep the secrets of Chrome, we won't be able to participate in the Webkit community. ' We'd like to be able to help Webkit in some ways, ' said Fisher. ' We have a lot of experienced developers, and we'd like to know what challenges people are facing and are willing to help. '

With the release of Chrome, Fisher said his team members sometimes dined with Webkit and some of them became good friends in private. Fisher says they are eager to work with other Webkit development groups to solve the problem of offline databases.

Chrome also includes Google's Open-source Gears technology, which is designed to function as offline as HTML 5.

Gears can be seen as a substitute for an existing API, Fisher said, HTML 5 is a great thing for new browsers, but most users also use old browsers. Gears can get the same APIs from older browsers, and we're providing compatibility for the HTML version 5 API.

Gears compatibility is very good, and it's becoming another way to bring HTML 5 to people's desktops.

At present, most of the work is carried out by Apple,mozilla, Opera, Google and Trolltech. What is Microsoft doing? IE is known for its slow WEB standards, not to mention HTML 5. But IE8 could make a difference.

"We hope that the work we are starting now can create a test system in the HTML workgroup," said Chris Wilson, chairman of Microsoft IE Platform and WHAT Working Group, in the Mail. The IE Development Group is still concerned about some of the HTML 5 proposals, Wilson said. I think all members of the Working Group will admit that we still have a lot of work to do.

IE8, currently in beta, already contains many of the new features of HTML 5. It has a cross document messaging system, local storage, and some offline events to detect disruption to the network. But some features have not yet been put on the agenda, such as Canvas.

HTML 5 is very large and still in the development phase, I think the browser vendors should reach a consensus as soon as possible, and each browser's specific implementation time can choose their own. Web developers and browser vendors will agree with Wilson's remark that this is definitely an exciting moment and we want to see the web become a new application platform.

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