define(function(){
    var Event = {
        //页面加载完成后注册onload事件
        readyEvent:function(fn){
            if(fn == null){
                fn = document;
            }
            var oldonload = window.onload;
            if(typeof window.onload != 'function'){
                window.onload = fn;
            }else{
                // 如果window.onload上已有事件绑定，则追加到它的后面
                window.onload = function(){
                    oldonload();
                    fn();
                }
            }
        },
        bindEvent:function(target,type,handler){
            if(target.addEventListener){
                target.addEventListener(type,handler,false);
            }else if(target.attachEvent){
                target.attachEvent('on'+type,function(event){
                    // IE attachEvent注册的事件作为函数调用，其this值是全局对象，需要用call来修改其指向
                    return handler.call(target,event)
                })
            }else{
                target['on'+type] = handler;
            }
        },
        // 移除事件
        removeEvent:function(target,type,handler){
            if(target.removeEventListener){
                target.removeEventListener(type,handler,false);
            }else if(target.detachEvent){
                target.detachEvent('on'+type,handler);
            }else{
                target['on'+type] = null;
            }
        },
        // 阻止事件传播
        stopPropagation:function(event){
            if(event.stopPropagation){
                event.stopPropagation();
            }else{
                event.cancelBubble = true;
            }
        },
        // 取消事件默认行为
        preventDefault:function(event){
            if(event.preventDefault){
                event.preventDefault();
            }else{
                event.returnValue = false;
            }
        },
        // 获取事件目标
        getTarget:function(event){
            return event.target || event.srcElement;
        },
        // 获取事件对象的引用
        getEvent:function(event){
            var event = event || window.event;
            if(!event){
                // caller用于在函数内部获取调用getEvent的函数
                var c = this.getEvent.caller;
                while(c){
                    event = c.arguments[0];
                    if(event && Event == event.constructor){
                        break;
                    }
                    c = c.caller;
                }
            }
            return event;
        }
    }

    return Event;
})