1、index()
It returns the index of the current element in all sibling elements inside.
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<ul>
<li><a href="#">我是链接</a></li>
<li><a href="#">我是链接</a></li>
<li><a href="#">我是链接</a></li>
<li><a href="#">我是链接</a></li>
<li><a href="#">我是链接</a></li>
<li><a href="#">我是链接</a></li>
<li><a href="#">我是链接</a></li>
<li><a href="# "> I am a link </a> </ li>
the console.log ($ (the this) .index ());
// index () returns the index of the current element in all sibling elements inside.
$ (function () {
<Script>
<Script src =" jQuery-1.12.4 .js "> </ Script>
</ ul>
<li> <a href="#"> I link </a> </ li>
$ (" li "). the Click (function () {
});
});
</script>
</body>
</html>
2、