function setCookie(c_name,value,expire_days) {
	var exdate=new Date();
	exdate.setDate(exdate.getDate()+expire_days);
	document.cookie=c_name+ "=" +escape(value)+
		((expire_days==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 "";
}
var ahn_tz;
Event.observe(window, 'load', function() {
	ahn_tz = getCookie('ahn_tz');
	if(!ahn_tz) {
		var d = new Date();
		var tz = d.getTimezoneOffset() / 60;
		setCookie('ahn_tz', tz, 1);
	}
});