Ajax封装

/**
 * Ajax封装
 */
var Ajax = function(){
	this.isIE = !+ [ 1, ] ? true : false;
	this.xmlHttpList = [];
};
Ajax.prototype = {
	ajaxConnection : 0,
	getXmlHttp : function( count ){
		count = count != undefined ? count : 5;
		var bool = this.xmlHttpList.length === 0,i;
		var length = bool ? count : this.xmlHttpList.length;
		for(i=0;i<length;i++){
			if(bool){
				this.xmlHttpList.push(this.isIE ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest()); 
			}else{
				if(this.ajaxConnection > length){//高并发时候,少了就添加连接
					this.xmlHttpList.push(this.isIE ? new ActiveXObject("Microsoft.XMLHTTP") : new XMLHttpRequest());
					i = length;
					break;
				}
				if(this.xmlHttpList[i].readyState === 0)break;
			}
		}
		return this.xmlHttpList[ bool ? 0 : i ];
	},
	post : function(url,yesFun,noFun){
		this.ajax("post",url,yesFun,noFun);
	},
	get : function(url,yesFun,noFun){
		this.ajax("get",url,yesFun,noFun);
	},
	ajax : function(type,url,yesFun,noFun){
		var xmlHttp = this.getXmlHttp();
		xmlHttp.open(type, url, true);
		xmlHttp.onreadystatechange = function() {
			if (xmlHttp.readyState == 4 && xmlHttp.status == 200) {
				if( yesFun && typeof yesFun === 'function' ){
					yesFun( xmlHttp.responseText );
				}
				xmlHttp.abort();
				Ajax.ajaxConnection --;
			}else{
				if (xmlHttp.readyState == 4 && xmlHttp.status != 200) {
					if( noFun && typeof noFun === 'function' ){
						noFun( xmlHttp.readyState );
					}
					xmlHttp.abort();
					Ajax.ajaxConnection --;
				}
			}
		};
		xmlHttp.send(null);
	}
};
//使用方法
 var ajax = new Ajax();
	     ajax.post("?GchartID="+id,function(html){
                            alert(html);
		 },function(state){
			 alert("请求错误:"+state);
		 });