jQuery-like ajax function (not for MSIE).js

function ajax(obj) {
    // data
    obj.type = obj.type ? obj.type.toUpperCase() : "GET";
    obj.data = obj.data || "";
    obj.dataType = obj.dataType || "application/x-www-form-urlencoded";
    obj.aborted = false;
 
    // callbacks
    obj.success = obj.success || function() {};
    obj.error = obj.error || function() {};
    
    // init XHR
    var xhr, xhrs = array();
    if(typeof XMLHttpRequest !== "undefined" ) {
        xhrs.push([XMLHttpRequest, undefined]);
    } else if(typeof ActiveXObject !== "undefined") {
        xhrs.push([ActiveXObject,"Microsoft.XMLHTTP"]);
        xhrs.push([ActiveXObject,"Msxml2.XMLHTTP"]);
        xhrs.push([ActiveXObject,"Msxml2.XMLHTTP.3.0"]);
    }

    for(var i=xhrs.length;i--;) {
        try {
            xhr = new xhrs[i][0](xhrs[i][1]);
            if(xhr) {
                break;
            }
        } catch(e) {}
    }

    xhr.onreadystatechange = function() {
        if(this.readyState == 4 && !obj.aborted) {
            switch(this.status) {
                case 200:
                    obj.success.call(obj, this);
                    break;
                default:
                    obj.error.call(obj, this);
                    break;
            }
 
            if("timer" in obj) {
                clearTimeout(obj.timer);
            }
            
            // IE memory leak
            this.onreadystatechange = function(){}
        }
    }
 
    xhr.open(obj.type, obj.url, true);
    if(obj.type === "POST") {
        xhr.setRequestHeader("Content-type", obj.dataType);
        xhr.setRequestHeader("Content-length", obj.data.length);
        xhr.setRequestHeader("Connection", "close");
    }
    if("timeout" in obj && obj.timeout > 0) {
        obj.timer = window.setTimeout(function() {
            obj.aborted = true;
 
            xhr.abort();
            obj.error.call(obj, xhr);
            xhr = null;
            clearTimeout(obj.timer);
        }, obj.timeout);
    }
 
    xhr.send(obj.data);
}