Untitled

<html>
<head>
</head>
<body>
<div id="container" style="height:100%;width:100%">
  <div id="left" style="background-color:red; height:100%;width:300px;float:left">
  a
  </div>
  <div id="center" style="background-color:blue;height:100%;width:100%;">
  b
  </div>
</div>
</body>
</html>