What's new in HTML 5.0? Part 3: Document structure. Conclusion
Unlike previous versions of HTML and XHTML, which are defined by browsers by their syntax, HTML 5 is defined depending on the Document Object Model (DOM) - the structure (“tree”) of the document is read by the browser to display the page. For example, consider a very simple document consisting of a heading, a subtitle, and some text. The DOM structure will look like this:
To an illustration: the structure of a DOM document consists of the “title” element in the “h1” and “p” heading elements in the document body.
The advantages of this definition of HTML 5 according to the DOM rules are that the language itself can be defined independently of the syntax. There are primarily two syntaxes that can be used to represent HTML documents: the HTML series (HTML 5) and the XML series (XHTML 5).
The HTML series refers to the syntax that comes from SGML earlier versions of HTML, but is defined for compatibility with browsers, in fact, in practice as HTML.
To an illustration: the structure of a DOM document consists of the “title” element in the “h1” and “p” heading elements in the document body.
The advantages of this definition of HTML 5 according to the DOM rules are that the language itself can be defined independently of the syntax. There are primarily two syntaxes that can be used to represent HTML documents: the HTML series (HTML 5) and the XML series (XHTML 5).
The HTML series refers to the syntax that comes from SGML earlier versions of HTML, but is defined for compatibility with browsers, in fact, in practice as HTML.
<!DOCTYPE html>
An HTML Document
Example
This is an example HTML document.
<!DOCTYPE html>
An HTML Document
Example
This is an example HTML document.
<!DOCTYPE html>
An HTML Document
Example
This is an example HTML document.
')
Note that in previous versions of HTML, some tags are optional and are added automatically.
The XML series refers to the syntax used in XML 1.0, exactly like XHTML 1.0.
An HTML Document
Example
This is an example HTML document.
If you do not take into account the differences in the spaces, as well as the presence of the xmlns attribute, these two examples are equivalent.
Browsers use MIME types to distinguish between these documents. Any document submitted as " text / html " must comply with the requirements for the HTML series, and any document with XML MIME type as application / xhtml + xml must meet the requirements for the XML series.
Developers must consciously choose one or another series, which affects many factors. Do not dwell on the constant choice of any one type, because each one is optimized for different situations.
HTML benefits
1. Backwards compatible with existing browsers .
2. Developers are already familiar with the syntax.
3. The syntax used means that the user will not encounter the Yellow Screen of Death if the error has accidentally slipped out.
4. Convenient short syntax, for example, developers can skip several tags and attributes.
Benefits of using XHTML
1. The strict XML syntax forces developers to write well-marked code that other developers can figure out.
2. Integrates directly with other XML dictionaries, such as SVG and MathML
3. Allows the use of XML Processing, which some authors use as part of the editing and / or posting process.
Want to help HTML 5 developers?
Work on HTML 5 continues, and will continue for several years. Testing, the requirement to achieve maximum compatibility with different browsers, various evaluation work - all this may take about 15 years . In the course of these developments, communication with a wide range of people, including web designers and developers, vendors and vendors of browsers is vital to ensure its success in releasing these developments.
In addition to the specification, there are a number of other related works to help people better understand the design process.
1. Differences from HTML 4 describe the changes that have affected past HTML versions.
2. The principles of HTML design describe the basic rules that will help make decisions and understand many of the existing principles of development.
3. HTML 5 Web Developer Guide , started only recently. Its task is to help web designers and developers to better understand the innovations of HTML 5, to convey the experience of the best developers
There are many ways in which you can contribute to the development of HTML 5. You can join the W3C's HTML WG or subscribe to the HTML WG or WIKI . You can also subscribe to any of the WHATWG mailings, chat on the WHATWG forum , add a comment or write articles to the WHATWG blog .
Thank you for attention.
Source: https://habr.com/ru/post/31404/
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