Determine whether it is html5

With the continuous development of the Internet, HTML, as the basic language for web development, is also constantly updated. As the latest version, HTML5 has richer tags, more powerful APIs and more flexible features, and has become the mainstream of modern web development.

However, it is not easy to determine whether a web page adopts HTML5, because HTML5 is still compatible with the tags and attributes of the old version of HTML. Next, this article will introduce you to several methods to determine whether a web page uses HTML5.

Method 1: View the document type declaration (doctype)

At the beginning of the HTML document, there is usually a document type declaration (DOCTYPE). In HTML5, the document type is declared as (note the case).

Therefore, if the document type of a web page is declared as , then this web page uses HTML5.

But it should be noted that not all web pages require a document type declaration. If a web page does not have a document type declaration, it does not mean that the web page does not use HTML5.

Method 2: Check whether new semantic tags and attributes are used in the page

HTML5 introduces many new semantic tags, such as <header></header>, <nav></nav>, <article></article>, <section></section>, and <footer></footer>, etc. At the same time, HTML5 also introduces some new attributes, such as data-* and role.

Therefore, if the above new tags and attributes appear in a web page, then this web page uses HTML5.

But it should be noted that the correct use of new tags and attributes does not mean that this web page uses HTML5. Because it is possible that these tags and attributes are dynamically created through JavaScript.

Method 3: Check whether new APIs and features are used in the page

HTML5 introduces many new APIs and features, such as Canvas, Web Storage , Web Workers, Geolocation, Audio and Video, etc. At the same time, HTML5 also supports some new features, such as contenteditable, placeholder, and autofocus.

Therefore, if a web page uses the above new APIs and features, then this web page uses HTML5.

But it should be noted that correct use of new APIs and features does not mean that this web page uses HTML5. Because these APIs and features can also be implemented through JavaScript simulation.

Method 4: View the source code of the web page

This is the most direct method. By viewing the source code in the web page, you can directly determine from the code whether the web page uses HTML5.

In the code, if new semantic tags, attributes or APIs appear, then this web page uses HTML5.

Summary

The above methods can help us determine whether a web page uses HTML5. However, it should be noted that none of the above methods are 100% accurate.

Because in actual development, we may use some techniques and means to confuse judgment. Therefore, when judging whether a web page uses HTML5, it is necessary to combine a variety of methods and techniques to make a comprehensive judgment.

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