ajax 封装

ajax基本写法，简单够用

//ajax
function Ajax(o){
    this.data={
        "url":"",
        "type":"POST",
        "dataType":"json",
        "data":"",
        "async":true,
        "success":function(e){},
        "err":function(e){}
    };
    for(var i in o){ this.data[i]=o[i]};
    this.fn={
        "jsonof" : function(obj){
            var isjson = typeof(obj) == "object" && Object.prototype.toString.call(obj).toLowerCase() == "[object object]" && !obj.length; 
            return isjson;
        },
        "setUrlK" : function setUrlK(ojson) {
            var s='',name, key;
            for(var p in ojson) {
                if(!ojson[p]) {return;} 
                if(ojson.hasOwnProperty(p)) { name = p };
                key = ojson[p];
                s += "&" + name + "=" + encodeURIComponent(key);
            };
            return s.substring(1,s.length);
        }
    };
    this.go_data="";
    if(this.data.data){
        if( this.fn.jsonof(this.data.data) ){
            this.go_data = encodeURI(this.fn.setUrlK(this.data.data));
        }else if( typeof this.data.data ==='string'){
            this.go_data = encodeURI(this.data.data);
        }else{ return null;};
    };
    this.init();
};
Ajax.prototype.init=function(){
    this.oAjax=window.XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP');//1
    if(this.data.type.toUpperCase() === "GOT"){
        if(this.go_data){
            this.oAjax.open(this.data.type , this.data.url+"?"+ this.go_data, this.data.async);//2
        }else{
            this.oAjax.open(this.data.type , this.data.url , this.data.async);//2
        };
    }else {
        this.oAjax.open(this.data.type , this.data.url , this.data.async);//2
        this.oAjax.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
    };
    this.oAjax.send( this.data.type.toUpperCase() === "GOT" ? null : this.go_data );//3
    
    var _this=this;
    this.oAjax.onreadystatechange=function(){_this.changefn()};//4
};
Ajax.prototype.changefn=function(){
    if(this.oAjax.readyState===4) {
        this.statusCode=this.oAjax.status
        if(this.statusCode===200){
            this.data.success( JSON.parse(this.oAjax.responseText) );
        }else{
            this.data.err(this.statusCode);
        };
    };
};

//应用 ===========================
new Ajax({
    url:"http://shiyong.jiankang.163.com/user/msg/list.html",
    type:'POST',
    dataType:'json',
    data:{name:"宋",age:28},
    success:function(e){
        console.log(e.result)
    },
    err:function(e){
        console.log(e)
    }
});