效果图如下： 
html源码：
<!DOCTYPE html>
<html lang=”en-US”>
<head>
<meta http-equiv=”Content-Type” content=”text/html; charset=UTF-8″ />
<title>New Pure CSS3 Progress Bars Demonstration</title>
<meta name=”description” content=”Pure CSS3 progress bars demonstration by inWebson.com”/>
<meta name=”keywords” content=”demonstration,demo,css3,progress,bar,loading,preloader,inwebson”/>
<link rel=”stylesheet” media=”all” href=”vendor.css”>
<link rel=”stylesheet” media=”all” href=”style.css”>
<script src=”http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js”></script>
<script>
$(document).ready( function() {
var delay = 0;
$(‘.bar’).children(‘span’).each( function() {
var num = Math.floor(Math.random()*8)+2;
$(this)
.width(0)
.delay(delay)
.animate({
‘width’: (num*10)+’%’
}, 3000);
delay += 1500;
});
$(‘.source span’).on(‘click’, function() {
$(this)
.toggleClass(‘active’)
.next().slideToggle(700);
});
$(‘.source pre’).slideUp(0);
});
</script>
</head>
<body>
<!– Content –>
<section id=”wrapper”>
<div class=”content-inner”>
<section id=”basic-bar” class=”holder”>
<h3>基本类型</h3>
<div class=”bar color0″>
<span></span>
</div>
<div class=”source”>
<span>View Source</span>
<pre>
<!– HTML –>
<div class=”bar color0″>
<span></span>
</div>
<hr/><!– CSS –>
.bar {
margin: 5px 0 3px;
border: 6px solid #333;
background: #333;
overflow: hidden;
border-radius: 50px;
-moz-border-radius: 50px;
-webkit-border-radius: 50px;
box-shadow: 1px 1px 1px #777;
-moz-box-shadow: 1px 1px 1px #777;
-webkit-box-shadow: 1px 1px 1px #777;
}
.bar > span {
display: block;
height: 20px;
border-radius: 5px;
-moz-border-radius: 5px;
-webkit-border-radius: 5px;
}
.color0 > span {
background-color: #FF9932;
}
</pre>
</div>
</section>
<section id=”gradient-bar” class=”holder”>
<h3>绿色渐变</h3>
<div class=”bar gradient color1″>
