var viewportwidth;
var viewportheight;

function sizeadjust() {

	// 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
	}

	var contentheight = $("#mainbar").height();
	var adjustedheight = viewportheight - contentheight;

	if (adjustedheight > 300)
		$("#footerbar").css("height", adjustedheight + "px");

}