HTML & CSS

(1) The difference between ID and class

The ID only corresponds to one component, each page can be used only once; class corresponds to a Class (group) of components, one page can be used multiple times, and the same CSS is used for components of the same class.

(2) The difference between Div and span

Div and span can use the ID and class to define categories, and use the corresponding CSS style, but the fundamental difference between Div and CSS is that the DIV is a line, each with a div will be wrapped, use span does not wrap, contains the content of how long to occupy the page.