window.addEvent("load",function(){
	rs();
});
window.addEvent("resize",function(){
	rs();
});
function rs(){
	W = window.getWidth();
	if($("back_left")){
		$("back_left").setStyle("width", ((W/2)+10));
		$("back_left").style.height = ($("header").offsetHeight + $("main").offsetHeight)+"px";
	}
	if($("back_right")){
		$("back_right").setStyle("width", (W/2));
		$("back_right").style.height = ($("header").offsetHeight + $("main").offsetHeight)+"px";
	}
}