为啥会出现警告？

为什么会出现警告？？
var xmlhttp;
function $(id){
return document.getElementById(id);
}
function createXmlHttpRequest(){
try {
xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try {
xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e1) {
try {
xmlhttp = new XMLHttpRequest();
if(xmlhttp.overrideMimeType){
xmlhttp.overrideMimeType("text/xml");
}
} catch (e2) {
}
}
}
}
function update(bid,price){
createXmlHttpRequest();
var count = $("count").value;
var url = "Modify?bid="+bid+"&count="+count+"&price="+price;

xmlhttp.open("post", url, true);
xmlhttp.onreadystatechange = function(){
if(xmlhttp.readyState == 4){
if(xmlhttp.status == 200){
var str = xmlhttp.responseText;
var price = $("price").value;
var t_price = count*price;
total.innerHTML = ""+t_price+"";
}
}
}这个地方会出现警告（就旁边这个中括号）。不知道为什么？
xmlhttp.send(null);
}

[解决办法]
这样不报错了。

JScript code

var xmlhttp;function $(id){    return document.getElementById(id);}function createXmlHttpRequest(){    try {        xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");    } catch (e) {        try {            xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");        } catch (e1) {            try {                xmlhttp = new XMLHttpRequest();                if(xmlhttp.overrideMimeType){                    xmlhttp.overrideMimeType("text/xml");                }            } catch (e2) {            }        }    }}function update(bid,price){    createXmlHttpRequest();    var count = $("count").value;    var url = "Modify?bid="+bid+"&count="+count+"&price="+price;    xmlhttp.open("post", url, true);    xmlhttp.onreadystatechange = function(){        if(xmlhttp.readyState == 4){            if(xmlhttp.status == 200){                var str = xmlhttp.responseText;                var price = $("price").value;                var t_price = count*price;                total.innerHTML = ""+t_price+"";            }        }    }    xmlhttp.send(null);}