function showdiv(divid,showtype){
		document.getElementById(divid).style.visibility = showtype
	}
	function calcleft(){
		windowwidth = document.body.clientWidth
		pagewidth = 660
		divwidth = (windowwidth - pagewidth)/2
		//510
		divleft = (300 + divwidth)
		//alert(divleft)
		document.getElementById('navdiv').style.left = divleft
	}
	calcleft()