jsonp和事件发布监听

模拟jsonp

 var id = 0;
 function JSONP(url,param,cb){
     var callbackName = "json_" + id++;
     var arg = Array.prototype.slice.call(arguments);
     var _cb = arg.pop();
     window[callbackName] = function(data){
         head.removeChild(scriptNode);
         window[callbackName] = null;
         if(typeof _cb == "function"){
             _cb(data);
         }
     }
     var _url = url.replace("callback=?","callback="+callbackName);
     if(param){
         var arr = [];
         for(i in param){
             arr.push(i+"="+arr[i]);
         }
         _url += "&"+arr.join("&");
     }
     var head  =document.getElementsByTagName("head")[0];
     var scriptNode = document.createElement("script");
     scriptNode.src = _url;
     head.appendChild(scriptNode);

 }

事件绑定/发布

 function EventMachine(){
     var _o  = {};
     this.bind = function(e,cb){
         if(!_o[e]){
             _o[e] = [];
         }
         _o[e].push(cb);
     }
     this.trigger = function(e,param){
         if(arguments.length==2&&Object.prototype.toString.call(param) == "[object Array]"){
             var arg = param;
         }else{
             var arg = Array.prototype.slice.call(arguments,1);
         }
         if(_o[e]&&_o[e].length>0){
             for(var i=0,l=_o[e].length;i<l;i++){
                 _o[e][i].apply(this,arg);
             }
         }
     }
 }