<!DOCTYPE html>
<html>
<head>
<style>
div {
    width: 200px;
}
</style>
</head>
<body>
<div id=letterSpacing>foobar foobar foobar foobar</div>
<div id=wordSpacing>foobar foobar foobar foobar</div>
<script>
document.body.offsetHeight;
letterSpacing.style.letterSpacing = "10px";
wordSpacing.style.wordSpacing = "20px";
</script>
</body>
</html>