6_兼容性.html

<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			.box{
				background-color: green;
				overflow: hidden;
				zoom:1;
			}
			.item{
				height: 50px;
				background-color: red;
				margin-top: 50px;
			}
			.mt100{
				margin-top: 100px;
			}
		</style>
		<!--
			1、margin-top传递
				触发BFC、haslayout
			2、上下margin叠压
				尽量使用同一方向的margin，比如都设置top或者bottom，
		-->
	</head>
	<body>
		<div class="box">
			<div class="item"></div>
			<div class="item mt100"></div>
		</div>
	</body>
</html>