<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="Generator" content="EditPlus®">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
<title>Document</title>
<style>
.box{
width: 200px;
height: 20px;
background:#ccc;
border-radius:10px;
position:relative
}
.clip{
position: absolute;
width: 100%;
height: 100%;
clip: rect(0px,100px,20px,0px); /* 第二个参数为进度值，当前进度为50%，100%对应200px */
background: red;
border-radius:10px;
}
</style>
</head>
<body>
<div class='box'>
<span class='clip'></span>
</div>
</body>
</html>
