ajax.js

一个很好的Ajax类,实现了XmlHttpRequest对象池功能.

// JScript 文件
var XmlHttp = {

    _objPool : [],

    _getRequest : function ()
    {        
        for(var i=0; i < this._objPool.length; i++)
        {
            if(this._objPool[i].readyState == 0 || this._objPool[i].readyState == 4)
            {
                return this._objPool[i];
            }
        }
        this._objPool[this._objPool.length] = this._createObj();
        return this._objPool[this._objPool.length - 1];
    },
    
    _createObj : function()
    {
        if (window.XMLHttpRequest)
        {
            var objXMLHttp = new XMLHttpRequest();
        }
        else
        {
            var MSXML = ['MSXML2.XMLHttp.5.0', 'MSXML2.XMLHttp.4.0', 'MSXML2.XMLHttp.3.0', 'MSXML2.XMLHttp', 'Microsoft.XMLHttp'];
            for(var n = 0; n < MSXML.length; n ++)
            {
                try
                {
                    var objXMLHttp = new ActiveXObject("Microsoft.XMLHTTP");
                    break;
                }
                catch(e)
                {
                }
            }
        }              
        if (objXMLHttp.readyState == null)
        {
            objXMLHttp.readyState = 0;
            objXMLHttp.addEventListener("load", function ()
            {
                objXMLHttp.readyState = 4;
                if (typeof objXMLHttp.onreadystatechange == "function")
                {
                    objXMLHttp.onreadystatechange();
                }
            },  false);
        }
        return objXMLHttp;
    },

    postRequest : function(url, data, isAnsyc, callback, objOut)
    {
        var objXMLHttp = this._getRequest();
        if(url.lastIndexOf("?") >=0)
            url += "&" + new Date().getTime();
        else url += "?" + new Date().getTime();
        objXMLHttp.open('post', url, isAnsyc);
        objXMLHttp.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
        objXMLHttp.send(data);
        objXMLHttp.onreadystatechange = function()
        {
            callback(objXMLHttp, objOut);
        };
        if(!isAnsyc)
            callback(objXMLHttp, objOut);
    },
    
    length : function()
    {
        return this._objPool.length;
    }
};