css基本选择器

 1 <!doctype html>
 2 <html lang="en">
 3     <head>
 4         <meta charset="UTF-8">
 5         <meta name="Generator" content="EditPlus®">
 6         <meta name="Author" content="">
 7         <meta name="Keywords" content="">
 8         <meta name="Description" content="">
 9         <title>Document</title>
10         <style type="text/css">
11             div{
12                 width:300px;
13                 height:30px;
14                 background:yellow;
15             }
16             #heizi{
17                 width:200px;
18                 height:20px;
19                 background:blue;
20             }
21             .objk{
22                 width:100px;
23                 height:10px;
24                 background:green;
25             }
26         </style>
27         <!--
28             class相当于名字， 而id相当于是身份证(唯一性);所有当多个同类标签需要用到同一样式时需要用class(可以有多个名称); 
29         -->
30     </head>
31     <body>
32         <div id="heizi">小猪佩奇</div>
33         <div class="ojbk ooo pppp mmm">可爱龙猫</div>
34         <div class="objk" style="500px;height:50px;background:pink;">泡泡小鱼</div>
35     </body>
36 </html>