console 命令行工具 X clear
console
<!DOCTYPE html>
<html lang="en">

<head>
	<meta charset="UTF-8" />
	<meta http-equiv="X-UA-Compatible" content="IE=edge" />
	<meta name="viewport" content="width=device-width, initial-scale=1.0" />
	<title>Document</title>
	<style>
		.a {
            margin-left:100px;
            width:100px;
            height:100px;
			float: left;
			position: relative;
			border: 1px solid green;
		}

		.b {
            left:10px;
            top:10px;
			position: absolute;
			
			border: 1px solid red;
		}

	</style>
</head>

<body>
	<div class="a">
		<div class="b">
			<span>我我我我我我我我我我我我我我我</span>
        </div>
    </div>


</body>
<script>
    alert($("body").css("position"));   
</script>

</html>