In HTML, class specifies the class name of the element, and the syntax format is " ". The class attribute is most often used to point to a class in a style sheet. However, you can also use it to change HTML elements with specified classes through JavaScript.

The operating environment of this tutorial: Windows 7 system, CSS3&&HTML5 version, Dell G3 computer.

The class attribute specifies the class name (classname) of the element.

The class attribute is most often used to point to a class in a style sheet. However, it can also be used to change HTML elements with a specified class through JavaScript.

Tips and Notes

Note: The class attribute cannot be used in the following HTML elements: base, head, html, meta, param, script, style and title.

Tip: You can assign multiple classes to HTML elements, for example:. This allows you to combine several CSS classes into one HTML element.

Tip: The class name cannot start with a number! Only Internet Explorer supports this practice.

Grammar

Example:

   
  
Header 1
 
A paragraph.
 
请注意这个重要的段落。:)
  

Effect:

##Extended information:

id attribute

The id attribute specifies the unique id of the HTML element.

id must be unique within the HTML document.

The id attribute can be used as a link anchor to change or add styles to an element with a specified id via JavaScript (HTML DOM) or via CSS.

Differences between HTML 4.01 and HTML5

In HTML5, the id attribute can be used on any HTML element (it will validate any HTML element. But it is not necessarily useful).

In HTML 4.01, the id attribute cannot be used for: , , , , ,

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