<script language="javascript">
var xmlhttp;

function ScoreTest(){
    var strErr=""
    var iWrongs=0;
    for (var i=0;i<=20;i++){
            if (parseInt(i)<10)
                x="0"
            else
                x="";
            var e=document.getElementById("DLChinese_ctl"+ x + i +"_txtInput");
            if (e==null) e=document.getElementById("DLChinese_txtInput_"+i);
            var h=document.getElementById("hd"+ i);
            if (e.value==h.value){
                $$('spn'+h.value+'1').style.display='inline';
                $$('spn'+h.value+'2').style.display='none';
                $$('spn'+h.value+'3').style.display='none';
            }else{
                $$('spn'+h.value+'1').style.display='none';
                $$('spn'+h.value+'2').style.display='none';
                $$('spn'+h.value+'3').style.display='inline';
                strErr=strErr+"|"+h.value;
                iWrongs=iWrongs+1;
            }
    }
    
    setTestResult("SaveTestRes.aspx?Unit=6&BookID=3&StepID=1&WrongList="+strErr);
    
    $$('hfWrongWords').value=strErr;
    alert('有'+iWrongs+'个单词拼写错误！');
    if (iWrongs>0) 
        $$('HidIWrongs').value=iWrongs;
    $$('BtnEndTest').style.display='none';
    return false;
}

function setTestResult(strURL){
    createXMLHTTPRequest();
    xmlhttp.open("GET",encodeURI(strURL));
    xmlhttp.onreadystatechange=HandleStateChange;
    xmlhttp.send(null);
}

function createXMLHTTPRequest(){
    if (window.XMLHttpRequest){
        xmlhttp=new XMLHttpRequest();
    }else if(window.ActiveXObject)
        xmlhttp=new ActiveXObject("Msxml2.XMLHTTP");
    if (!xmlhttp)
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}

function HandleStateChange(){
    if(xmlhttp.readyState==4){
        if (xmlhttp.status==200){
            alert("拼写错误：" +xmlhttp.responseText);
        }
    }
}
</script>

调用 scoreTest时setTestResult 为什么没有执行呢？

function setTestResult(strURL) {
        createXMLHTTPRequest();
        xmlhttp.open("GET", encodeURI(strURL));
        xmlhttp.onreadystatechange = HandleStateChange;
        xmlhttp.send(null);
alert('启动了AJAX')///////////
    }

    function HandleStateChange() {
        if (xmlhttp.readyState == 4) {
            if (xmlhttp.status != 200) {////////应该是不等于200吧。。==200就是正常的了
                alert("拼写错误：" + xmlhttp.responseText);
            }
             else alert('请求成功！')
        }
    }

------解决方案--------------------

用IE工具单步下看执行到哪里不执行