JavaScript cracking [3] Using className attribute_javascript skills

Javascript can also flexibly change the CSS class selector of a tag element through the className attribute to achieve style changes. A trinity page
The Structure of a webpage is created by HTML or XHTML;
The Presentation layer of a webpage is created by CSS;
Behavior is implemented by Javascript and DOM;


In fact, the presentation layer and behavior layer of a webpage always exist, even if the user does not define it. Because Web browsers load their default styles and events to the Web page structure layer.

B. Use the className attribute
Javascript can also flexibly change the CSS class selector of a tag element through the className attribute to achieve style changes.
Sample Code:

The Code is as follows:

Append CSS category