现在Ajax技术越来越流行了，出现了许多的服务器端框架，可以像以前写服务器端代码一样来使用Ajax，但是我还是觉得那样有些麻烦，不如直接用javascript来的简单、方便，从网上找到一段代码，实现了Ajax连接池，觉得不错，大家共享吧。
var Request = new function()
{
this.pool = new Array();
this.getXMLHttp = function (chunnel)
{
if(chunnel != null)
{
for (var a = 0; a < this.pool.length; a++)
{
if(this.pool[a]["chunnel"] == chunnel)
{
if(this.pool[a]["obj"].readyState == 0 || this.pool[a]["obj"].readyState == 4)
{
return this.pool[a]["obj"];
}
else
{
return "busy";
}
}
}
this.pool[this.pool.length] = new Array();
this.pool[this.pool.length - 1]["obj"] = this.createXMLHttp();
this.pool[this.pool.length - 1]["chunnel"] = chunnel;
return this.pool[this.pool.length - 1]["obj"];
}
for (var i = 0; i < this.pool.length; i++)
{
if (this.pool[i]["obj"].readyState == 0 || this.pool[i]["obj"].readyState == 4)
{
return this.pool[i]["obj"];
}
}
this.pool[this.pool.length] = new Array();
this.pool[this.pool.length - 1]["obj"] = this.createXMLHttp();
this.pool[this.pool.length - 1]["chunnel"] = "";
return this.pool[this.pool.length - 1]["obj"];
}
this.createXMLHttp = function ()
{
if(window.XMLHttpRequest)
{
var xmlObj = new XMLHttpRequest();
}
else
{
var MSXML = ['Microsoft.XMLHTTP', 'MSXML2.XMLHTTP.5.0', 'MSXML2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP'];
for(var n = 0; n < MSXML.length; n++)
{
try
{
var xmlObj = new ActiveXObject(MSXML[n]);
break;
}
catch(e)
{
}
}
}
return xmlObj;
}
this.reSend = function (url,data,callback,chunnel)
{
var objXMLHttp = this.getXMLHttp(chunnel)
if(typeof(objXMLHttp) != "object")
{
return ;
}
url += (url.indexOf("?") >= 0) ? "&nowtime=" + new Date().getTime() : "?nowtime=" + new Date().getTime();
if(data == "")
{
objXMLHttp.open('GET' , url, true);
objXMLHttp.send('');
}
else
{
objXMLHttp.open('POST' , url, true);
objXMLHttp.setRequestHeader("Content-Length",data.length);
objXMLHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
objXMLHttp.send(data);
}
if(typeof(callback) == "function" )
{
objXMLHttp.onreadystatechange = function ()
{
if (objXMLHttp.readyState == 4)
{
if(objXMLHttp.status == 200 || objXMLHttp.status == 304)
{
callback(objXMLHttp)
}
else
{
alert("Error loading page\n"+ objXMLHttp.status +":"+ objXMLHttp.statusText);
}
}
}
}
}
}