求教：我在本地建立一个html文件，想获得网络数据，点击“上证指数”按钮成功，其他两个按钮失败。 - 编程论坛

<!DOCTYPE HTML>
<html>
    <head>
        <title>Cross Origin Test</title>
    </head>
    <script type="text/javascript">
        var httpRequest;

        function getFromNet(url)
        {
            httpRequest = null;
            httpRequest = new XMLHttpRequest();
            if (httpRequest != null)
            {
                httpRequest.onreadystatechange = handleResponse;
                httpRequest.open("GET", url, true);
                httpRequest.send();
            }
        }

        function handleResponse()
        {
            if (httpRequest.readyState==4)  // loaded
            {
                if (httpRequest.status==200)  //OK
                {
                    //alert(httpRequest.responseText);
            document.getElementById("jieguo").value = httpRequest.responseText;
                }
            }
        }
    </script>
    <body>
        <button onclick = "getFromNet('http://qt.')">上证指数</button>
    <button onclick = "getFromNet('https://hq.')">沪深股票列表</button>
    <button onclick = "getFromNet('http://www.')">华能国际质押</button>
    <p/>
    <textarea id = jieguo style = "width:60em;height:20em"></textarea>
    </body>
</html>