We would like to know how to before: content and style.
<!DOCTYPE html>
<html>
<head>
<style type='text/css'>
#test_div:before {<!--from w w w .j a va 2s . co m-->
position: absolute;
width: 100%;
padding: 10px;
top: 0;
content: '';
left: 2px;
background: red;
height: 1px;
}
#test_div {
border: 1px solid #E3E3E3;
border-top: 0;
width: 300px;
height: 250px;
position: relative;
}
</style>
</head>
<body>
<div id="test_div"></div>
</body>
</html>
The code above is rendered as follows: