function IsoLogo () {
	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
	}
	
	if ( viewportheight < 670 ) {
		//$('footer_image').style.top = viewportheight-80 +'px';
	}
	if ( viewportheight > 670 ) {
		//$('footer_image').style.top = '590px';
	}
}

window.onresize = IsoLogo;