Ajax不返回数据？

function getNewContent(){
    var request = getHTTPObject();
    if(request){
        request.open('GET','example.txt',true);
        request.onreadystatechange = function(){
            if(request.readyState == 4){
                var para = document.createElement('p');
                var txt  = document.createTextNode(request.responseText);
                para.appendChild(txt);
                document.getElementById('new').appendChild(para);
            }
        };
        request.send(null);
    }else{
        alert("sorry,your browser don't support XMLHTTPRequest");
    }
}
addLoadEvent(getNewContent);

看javascript DOM编程艺术第7章的例子，写好后页面空白不显示example.txt中的数据。

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example.txt是个文件名，应该是个uri才行啊，类似http://localhost/example.txt

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请求一个Json串试试,类似jq的getJson()

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你自己在example. txt写有内容吗