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);
            }
        }
    }
}