题目提供的答案不对,经测试以下代码可以:
.top{height:100px; background:#ccc;width:100%;}
.main{background:red;position:relative;}
.left{ width:200px; height:500px; background:blue;position:absolute;left:0;top:0; }
.right{ margin-left:210px;height:500px; background:#9C9;}
.foot{ height:50px; background:#F63 }
.top{height:100px; background:#ccc;width:100%;}
.main{background:red;position:relative;}
.left{ width:200px; height:500px; background:blue;position:absolute;left:0;top:0; }
.right{ margin-left:210px;height:500px; background:#9C9;}
.foot{ height:50px; background:#F63 }
.top{height:100px; background:#ccc}
.main{height:500px;background-color: red;}
.left{ width:200px; height:500px; background:blue; position:absolute;}
.right{ margin-left:210px;height:500px; background:#9C9;position:absolute;width: 100%}
.foot{ height:50px; background:#F63 }
.main{height:500px;background-color: red;}
.left{ width:200px; height:500px; background:blue; position:absolute;}
.right{ margin-left:210px;height:500px; background:#9C9;position:absolute;width: 100%}
.foot{ height:50px; background:#F63 }