在Ajax返回多个值

<html>
<head>
<title>AjaxTest</title>
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest()
{
    if(window.ActiveXObject)
    {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    else if(window.XMLHttpRequest)
    {
        xmlHttp = new XMLHttpRequest();
    }
}
function startRequest()
{
    createXMLHttpRequest();
    try
    {
        xmlHttp.onreadystatechange = handleStateChange;
        xmlHttp.open("GET", "Json.txt", true);
        xmlHttp.send(null);
    }
    catch(exception)
    {
        alert("xmlHttp Fail");
    }
}
function handleStateChange()
{    
    if(xmlHttp.readyState == 4)
    {        
        if (xmlHttp.status == 200 || xmlHttp.status == 0)
        {
            var result = xmlHttp.responseText;
            var json = eval("(" + result + ")");
            alert(json.user);
            alert(json.sex);
        }
    }
}
</script>
</head>
<body>
    <div>
        <input type="button" value="AjaxTest" onclick="startRequest();" />
    </div>
</body>
</html>
Json.txt内容如下：
{
"user":"cck",
"sex":"name"
}