ajax实现google/baidu输入提示框

var http_request;
    function find(txt) {
        http_request = new ActiveXObject("Microsoft.XMLHTTP");
        http_request.onreadystatechange = function() {
            if (http_request.readyState == 4) {
                if (http_request.status == 200) {
                    var inputTxt = txt;
                    var xml = http_request.responseXML;
                    if (document.all.mydiv != undefined) {
                        document.all.mydiv.removeNode(true);
                    }
                    var list = xml.selectNodes("keys/key");
                    if (list.length > 0) {
                        var mydiv = document.createElement("div");
                        mydiv.id = "mydiv";
                        my