// From http://andylangton.co.uk/articles/javascript/get-viewport-size-javascript/	
function getWindowClientSize() 
{
	
	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.body.clientWidth;
	      viewportheight = document.body.clientHeight;
	}
	
	return {w:viewportwidth, h:viewportheight};
}