自己封装的myAjax，依赖jquery

;(function($) {
         var _params = {
             url:"",
             type:"",
             contentType:null,
             async:true,
             headers:{},
             data:null,
             success:function(){},
             error:function(){}
         };
         function loadXMLDoc() {
            var xmlhttp = null;
            if (window.XMLHttpRequest) {// code for all new browsers
              xmlhttp=new XMLHttpRequest();
            } else if (window.ActiveXObject) {// code for IE5 and IE6
              xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
            }
            return xmlhttp;
        }
        
    $.extend({
         minAjax:function(p){
            var params = $.extend({},_params,p);
            var xmlhttp = loadXMLDoc();
            if (xmlhttp!=null) {
                xmlhttp.onreadystatechange = function state_Change() {
                    if (this.readyState==4) {
                        if (this.status==200) {
                            p.success(this.responseText);
                        } else if(this.status == 401) {
                            console.log(this)
                            debugger;
                        }else if(this.status == 403) {
                            console.log(this)
                            debugger;
                        } else {
                            p.error(this);
                        }
                    }else {
                        //p.error("error XMLHttpRequest.readyState="+this.readyState);
                        //p.error(this);
                    }
                } 
                
                xmlhttp.open(params.type,params.url,params.async);
                var _contentType = "application/x-www-form-urlencoded";
                if(params.contentType) {
                    _contentType = params.contentType;
                }
                
                xmlhttp.setRequestHeader("Content-Type", params.contentType);
                try {
                    for ( i in params.headers ) {
                        xmlhttp.setRequestHeader( i, params.headers[ i ] );
                    }
                } catch( _ ) {}
              if(params.data) {
                 xmlhttp.send(params.data);
              }else {
                 xmlhttp.send(null);
              }
            } else {
               p.error("can't create XMLHttpRequest");
            }
         }
    });
    
})(jQuery);