function reSizeHeader () {
	 var headerlogo=document.getElementById("headerlogo");
	 var winwidth = document.body.clientWidth;
	 var imagewidth= winwidth-470;
	 headerlogo.style.width=imagewidth + "px";
	 var imageheight=imagewidth*0.0831;
	 headerlogo.style.height=imageheight +"px";
	 }