Note: the difference between the addClass() method and the attr() method: the
former is to add a style on the basis of the original style, and the latter is to replace the original style or set a style.
If you add multiple class attribute values to an element, it is equivalent to merging their styles. If different classes set the same style attributes, the latter will override the former.
Example 1:
<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title>Jquery对样式的操作</title>
<script src="jquery-1.11.3.js"></script>
<style>
.myClass{
font-weight: 900;
color:red;
}
.another{
font-style: italic;
color: blue;
}
</style>
</head>
<body>
<p title="你喜欢的运动" class="myClass">请选择你喜欢的运动？</p>
<ul id="sport">
<li>足球</li>
<li>王者荣耀</li>
<li>乒乓球</li>
<li>排球</li>
</ul>
<script>
//获取样式
/*$(function(){
var $_class=$("p").attr("class");
alert($_class)
});*/
//设置样式: 是将原来的样式替换为新的样式
$(function(){
$("p").attr("class","another");
});
</script>
</body>
</html>
For the use of attr() method, please pay attention to https://blog.csdn.net/qwy715229258163/article/details/113876646