if (typeof("getCookie") != 'function'){
	function setCookie(c_name,value,expiredays) { var exdate=new Date(); exdate.setDate(exdate.getDate()+expiredays); document.cookie=c_name+ "=" + escape(value)+ ((expiredays==null) ? "" : ";expires="+exdate.toGMTString()); }
	function getCookie(c_name) { if (document.cookie.length>0) { c_start=document.cookie.indexOf(c_name + "="); if (c_start!=-1) { c_start=c_start + c_name.length+1; c_end=document.cookie.indexOf(";",c_start); if (c_end==-1) c_end=document.cookie.length; return unescape(document.cookie.substring(c_start,c_end)); } } return ""; }
	function eraseCookie(name) { setCookie(name,"",-1); }
}

function create_transparent_bg(){
	var back_layer = document.getElementById('background_layer');
/*
	back_layer.style.width = document.body.clientWidth + "px";
	back_layer.style.height = document.documentElement.clientHeight + "px";	
*/	
	back_layer.style.width = document.documentElement.clientWidth + "px";
	back_layer.style.height = document.body.clientHeight+ "px";
	back_layer.style.display = "";
}

function destroy_transparent_bg(){
	var back_layer = document.getElementById('background_layer');
	back_layer.style.display = "none";
}