最近在用ajax开发服务器程序，发现IE浏览器不支持xmlhttprequest对象，而且找不到Microsoft.XMLHTTP控件。

问题出现了我们需要解决，解决方案如下：

1、运行下regsvr32 msxml3.dll；
2、用现成的框架来做ajax；
3、代码优化：

if(window.ActiveXObject)
    {
        xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    else if(window.XMLHttpRequest)
    {
        xmlHttp = new XMLHttpRequest();
    }

    if(handle_s == null)
        handle_s = "bin/normal.py/db";
    this.xmlHttp.onreadystatechange = handle_l;
    this.xmlHttp.open("GET",handle_s,true);
    this.xmlHttp.send(null);

或判断浏览器

var agt = navigator.userAgent.toLowerCase();
var is_ie = (agt.indexOf("msie") != -1);
var is_ie5 = (agt.indexOf("msie 5") != -1);
var is_opera = (agt.indexOf("opera") != -1);
var is_mac = (agt.indexOf("mac") != -1);
var is_gecko = (agt.indexOf("gecko") != -1);
var is_safari = (agt.indexOf("safari") != -1);

function CreateXmlHttpReq(handler) {

var xmlhttp = null;
if (is_ie) {
// Guaranteed to be ie5 or ie6
var control = (is_ie5) ? "Microsoft.XMLHTTP" : "Msxml2.XMLHTTP";

try {
xmlhttp = new ActiveXObject(control);
xmlhttp.onreadystatechange = handler;
} catch (ex) {
// TODO: better help message
alert("You need to enable active scripting and activeX controls");
}

} else {

// Mozilla
xmlhttp = new XMLHttpRequest();
xmlhttp.onload = handler;
xmlhttp.onerror = handler;

}

return xmlhttp;
}

或者

<script language="javascript">
    var http_request = false;
    function send_request(url) {//初始化、指定处理函数、发送请求的函数
        http_request = false;
        //开始初始化XMLHttpRequest对象
        if(window.XMLHttpRequest) { //Mozilla 浏览器
            http_request = new XMLHttpRequest();
            if (http_request.overrideMimeType) {//设置MiME类别
                http_request.overrideMimeType('text/xml');
            }
        }
        else if (window.ActiveXObject) { // IE浏览器
            try {
                http_request = new ActiveXObject("Msxml2.XMLHTTP");
            } catch (e) {
                try {
                    http_request = new ActiveXObject("Microsoft.XMLHTTP");
                } catch (e) {}
            }
        }
        if (!http_request) { // 异常，创建对象实例失败
            window.alert("不能创建XMLHttpRequest对象实例.");
            return false;
        }
        http_request.onreadystatechange = processRequest;