请问，这段投票的代码，会不会很容易被别人攻击？

  请问，这段投票的代码，会不会很容易被别人攻击？该如何改？        function vote(id, subjectID) {
  //  alert("不在投票时间段，请您先推荐!");
   // window.location.href="recommend.aspx?subjectID="+subjectID; 
           // return;
            if(deadlineFlag == 1)
            {
                alert("不在投票时间段，请您先推荐!");
window.location.href="recommend.aspx?subjectID="+subjectID; 
                return;
            }
            if(!confirm("是否真的要投票？")) {
              return;
            }
            var XMLHttp = CreateXMLHttp();
            var random = Math.random();
           var url = "../../../Ajax/AjaxVote.ashx?DataId=" + id + "&Random=" + random;
            XMLHttp.open("POST", url, true);
            XMLHttp.onreadystatechange = function OnHandler() {
                if (XMLHttp.readyState == 4) {
                    var result = XMLHttp.responseText;
                    alert(result.split("_")[0]);
                    if (result.indexOf("成功") != -1) {
                        var divId = "voteCountDIV" + id;
                        var totalVoteNum = result.split("_")[1];
                        document.getElementById(divId).innerHTML = "" + totalVoteNum + "票";
                    }
                }
            }
            XMLHttp.send(null);
        }