1.html is responsible for the structure, CSS is responsible for the style, JS responsible behavior.
CSS is written in the head tag inside the container style tag inside,
<style type= "Text/css" >
body{
Background-color:pink;
}
</style>
2. Tag Selector: Use tag pairs in HTML as selectors
(1) All the tags can be used as selectors, such as Body,h1,ul,span and so on.
(2) No matter how deep the current label is, it can be selected.
(3) The choice is all, not one.
3. Class Selector
Wording: <p class= "xxx bbb" > Hahaha </p>
(1) The so-called class is the class attribute, and its properties can be reused.
(2) The same tag can carry multiple classes at the same time, but must be separated by a space (the use of classes, you can determine the level of a person's CSS)
4.ID Selector
(1) Any label can have a id,id name to start with a letter, can be underlined, numbers, uppercase and lowercase strict distinction.
(2) The ID on the same page cannot be duplicated, even if it is a different label.
(3) is the ID or class used? Generally used in CSS Class,id most are used in JS
CSS Base Selector