.mainbox{width:960px;height:300px;background:#cff;}
.leftbox{width:740px;height:300px;background:#c9f;float:left;}
.rightbox{width:210px;height:300px; background:#fcf;float:right;}
</style>
</head>
<body>
<div class="mainbox">
<div class="leftbox"></div>
<div class="rightbox"></div>
</div>
