JavaScript Cookies

cookie.js

function setCookie(cname, cvalue, exdays) {
 var d = new Date();
 d.setTime(d.getTime() + (exdays*24*60*60*1000));
 var expires = "expires="+d.toUTCString();
 document.cookie = cname + "=" + cvalue + "; " + expires;
}

function getCookie(cname) {
 var name = cname + "=";
 var ca = document.cookie.split(';');
 for(var i=0; i<ca.length; i++) {
 var c = ca[i];
 while (c.charAt(0)==' ') c = c.substring(1);
 if (c.indexOf(name) == 0) return c.substring(name.length, c.length);
 }
 return "";
}

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