<html>
<head>
<style>
#div1{
background-color:green;
height:200px;
float:left;
200px;
}
#div2{
background-color:silver;
height:200px;
}
</style>
</head>
<body>
<div id="div1">div1</div>
<div id="div2">div2</div>
</body>
</html>