function bg_ac() {
    $("#arka_plan").css("left",0);
    $("#arka_plan").css("top",0);
    $("#arka_plan").width($(window).width());
    $("#arka_plan").height($(document).height());
    $("#arka_plan").css("opacity",0);
    $("#arka_plan").css("display","");
    $("#arka_plan").fadeTo("fast",0.5);
	}

 function pos_ayarla() {
	  ww = $(window).width();
	  wh = $(window).height();
    $("#background").css("height",(wh)+"px");
 }