** Wrong way of writing: If the id writes a number, the browser cannot parse it out, and it will not be able to output the style **
<style type="text/css">
#1001{
font-size: smaller;
color: red;
border: aqua solid 1px;
}
</style>
</head>
<body>
<div id="1001" >标签1aa</div>
Correct way of writing:
<!-- 注意此时的id 不能使用全数字进行选择-->
<style type="text/css">
#id1001{
font-size: smaller;
color: red;
border: aqua solid 1px;
}
</style>
</head>
<body>
<div id="id1001" >标签1aa</div>