set cookie with javascript

set_cookie.js

var KEY = '';
var VALUE = '';
var EXPIRES = 0;
var DOMAIN = '';
var PATH = '';
var expires = EXPIRES,
	days = expires,
	t    = expires = new Date();
	t.setDate(t.getDate() + days);
document.cookie = [
  encodeURIComponent(KEY),
  '=',
  encodeURIComponent(VALUE),
  '; expires=' + expires.toUTCString(),
  '; path=' + PATH,
  '; domain=' + DOMAIN
].join('');