Untitled

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
          "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
  <style>
html, body {
	height: 100%;
}
div {
  width: 50%;
  height: 100%;
  float: left;
}
#red_div {
  background-color: #f00;
}
#blue_div {
  background-color: #00f;
}
  </style>
</head>
<body>
  <div id="red_div" />
  <div id="blue_div" />
</body>
</html>