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 checkCookie(){
	username=getCookie('username');
	if (username!=null && username!="") {
		alert('Welcome again '+username+'!');
	}
	else {
		username=prompt('Please enter your name:',"");
		if (username!=null && username!="") {
			setCookie('username',username,365);
		}
	}
}