function getClientScreenSize()
{

	var viewportwidth;
	var viewportheight;

	// the more standards compliant browsers (mozilla/netscape/opera/IE7) use window.innerWidth and window.innerHeight
	if (typeof window.innerWidth != 'undefined')
	{
		viewportwidth = window.innerWidth,
		viewportheight = window.innerHeight
	}
	// IE6 in standards compliant mode (i.e. with a valid doctype as the first line in the document)
	else if (typeof document.documentElement != 'undefined'
			&& typeof document.documentElement.clientWidth != 'undefined' && document.documentElement.clientWidth != 0)
	{
		viewportwidth = document.documentElement.clientWidth,
		viewportheight = document.documentElement.clientHeight
	}
	// older versions of IE
	else
	{
		viewportwidth = document.getElementsByTagName('body')[0].clientWidth,
		viewportheight = document.getElementsByTagName('body')[0].clientHeight
	}

	document.getElementById('clientWidth').value = viewportwidth;
	document.getElementById('clientHeight').value = viewportheight;
}