{  
"programmers": [  
{ "firstName": "Brett", "lastName":"McLaughlin", "email": "brett@newInstance.com" },  
{ "firstName": "Jason", "lastName":"Hunter", "email": "jason@servlets.com" },  
{ "firstName": "Elliotte", "lastName":"Harold", "email": "elharo@macfaq.com" }  
],  
"authors": [  
{ "firstName": "Isaac", "lastName": "Asimov", "genre": "science fiction" },  
{ "firstName": "Tad", "lastName": "Williams", "genre": "fantasy" },  
{ "firstName": "Frank", "lastName": "Peretti", "genre": "christian fiction" }  
],  
"musicians": [  
{ "firstName": "Eric", "lastName": "Clapton", "instrument": "guitar" },  
{ "firstName": "Sergei", "lastName": "Rachmaninoff", "instrument": "piano" }  
]  
}  
  
通过异步调用，来读取json数据  
  
<html xmlns="http://www.w3.org/1999/xhtml" >  
<head runat="server">  
<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.programmers[0].firstName);//读取json数据  
            //alert(json.sex);  
        }  
    }  
}  
</script>  
</head>  
<body>  
    <div>  
        <input type="button" value="AjaxTest" onclick="startRequest();" />  
    </div>  
</body>  
</html>