wuheng
/
vip21-javaweb


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            width: 200px; height: 100px;
            background-color: aqua;
        }
        .demo1 {
            background-color: red;
        }
        #demo2 {
            background-color: black;
        }
    </style>
</head>
<body>

<div class="demo1" style="background-color: green">1</div>
<hr />
<div class="demo1">2</div>
<hr />
<div id="demo2">3</div>

</body>
</html>