<html>
<body style="overflow:hidden;">
<textarea id="ta" rows=10 cols=40>Sample text</textarea>
<script>
var v = document.getElementById('ta');
var w = v.offsetWidth; // Force a layout
v.rows += 40; // Change the rows again.
w = v.offsetWidth; // Force a layout again.
</script>
</body>
</html>