<script type="text/javascript">
  var Cookie={
  setCookie:function(name,value,option){
    var str=name+"="+escape(value);
    if(option){
      if(option.expireDays){
        var date=new Date();
        var ms=option.expireDays*24*3600*1000;
        date.setTime(date.getTime()+ms);
        str+=";expires="+date.toGMTString();
      }
      if(option.path)str+=";path="+path;
      if(option.domain)str+=";domain"+domain;
      if(option.secure)str+=";true";
    }
    document.cookie=str;
  },
  getCookie:function(name){
    var cookieArray=document.cookie.split("; ");
    var cookie=new Object();
    for(var i=0;i<cookieArray.length;i++){
      var arr=cookieArray[i].split("=");
      if(arr[0]==name)return unescape(arr[1]);
    }
    return "";
  },
  deleteCookie:function(name){
    this.setCookie(name,"",{expireDays:-1});
  }
}
Cookie.setCookie("user","jack");
alert(Cookie.getCookie("user"));
Cookie.deleteCookie("user");
alert(Cookie.getCookie("user"));
</script>