ajax的post提交

    <script language="javascript">
        var xmlHttpRequest = null;
        function selectionChanged() {
            // IE only.
            xmlHttpRequest = new ActiveXObject("Msxml2.XMLHTTP");
            string = "objstr=1";
            //发送数据
            xmlHttpRequest.open("POST", "A.aspx", false);//提交到A.aspx
            xmlHttpRequest.setrequestheader("content-length", string.length);
            xmlHttpRequest.setrequestheader("content-type", "application/x-www-form-urlencoded");
            xmlHttpRequest.send(string);

            xmlHttpRequest.onreadystatechange=onReadyStateChange;
        }

        function onReadyStateChange() {
            if (xmlHttpRequest.readyState == 4) {
                if (xmlHttpRequest.status == 200) {
                    var w= xmlHttpRequest.responseText;
                }
            }
        }
    </script>

    protected void Page_Load(object sender, EventArgs e)
    {
        Response.ContentType = "text/plain";

        string objstr= Request.Form["objstr"].ToString();

        Response.Write("Hello World"+objstr); 

        Response.End();
    }

另外，AJAX是不支持跨域提交的，这应该是浏览器的权限的