Determining a Browser’s Dimensions with Javascript
This is about as cross-browswer compatible as you can get:
<script type="text/javascript">
var winW, winH;
if (self.innerWidth) {
winW = self.innerWidth;
winH = self.innerHeight;
} else if (document.documentElement && document.documentElement.clientWidth) {
winW = document.documentElement.clientWidth;
winH = document.documentElement.clientHeight;
} else if (document.body) {
winW = document.body.clientWidth;
winH = document.body.clientHeight;
}
</script>