png图片入下

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
<title>Examples</title>
<meta name="description" content="">
<meta name="keywords" content="">
<link href="" rel="stylesheet">
</head>
<style type="text/css">
			*{
				padding: 0;
				margin: 0;
			}
			li{
				list-style: none;
			}	
			.box{
				width: 250px;
				margin: 100px auto;
			}
			.box li{
				float: left;
				width: 24px;
				height: 24px;
				background-color: pink;
				margin: 15px;
				background: url('1.png') no-repeat;
			}
</style>
<body>
	<div class="box">
		<ul>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
			<li></li>
		</ul>
	</div>
    <script type="text/javascript">
    	//1.获取元素 所有的小li
    	var lis = document.querySelectorAll('li');
    	for(var i = 0;i < lis.length;i++){
    		//让索引号 乘以44就是每个li的背景y坐标
    		var index = i * 44;
    		lis[i].style.backgroundPosition = '0 -' + index + 'px';
    	}
    </script>
</body>
</html>