<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>layout nonsense for blue</title>
<style type="text/css">
* {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
-ms-box-sizing: border-box;
-o-box-sizing: border-box;
box-sizing: border-box;
position: relative;
margin: 0;
padding: 0;
width: 100%;
}
html, body, textarea { height: 100%; border: 1px solid blue; }
div { height: 50%; }
</style>
</head>
<body>
<div><textarea></textarea></div>
<div><textarea></textarea></div>
</body>
</html>