cooke.js

cooke.js

/**
 * 
 * Usage:
 * Create/Update: Cookie.set("username", "John", 90);
 * Read: Cookie.get("username");
 * Destroy: Cookie.delete("username");
 * 
 */
var Cookie = {
  set: function (name,value,days) {
	  if (days) {
		  var date = new Date();
		  date.setTime(date.getTime()+(days*24*60*60*1000));
		  var expires = "; expires="+date.toGMTString();
	  }
	  else var expires = "";
	  document.cookie = name+"="+value+expires+"; path=/";
  },
  get: function (name) {
  	var nameEQ = name + "=";
  	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,c.length);
  		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  	}
  	return null;
  },
  delete: function (name) {
  	createCookie(name,"",-1);
  }
};

Explanation
http://www.quirksmode.org/js/cookies.html#script