事件監聽的相關兼容性

//事件監聽的兼容性寫法
var addEvent=function(elements,type,callback){
    if(elements.addEventListener){
        elements.addEventListener(elements,type,false)
    }else if(elements.attachEvent){
        elements.attachEvent("on"+type,callback)
    };
};

//事件移除的兼容性寫法
var removeEvent=function(elements,type,callback){
    if(elements.removeEventListener){
        elements.removeEventListener(elements,type,false)
    }else if(elements.detach){
        elements.detach("on"+type,callback)
    };
};

//獲取事件源的兼容性寫法
var getEvent=function(event){
    event = event || window.event;
    return event.target || event.srcElement;
};

//阻止事件冒泡的兼容性寫法
var stopPropagation = function(event){
    if(event.stopPropagation){
        event.stopPropagation();
    }else{
        event.cancelBubble = true;
    }
};

//阻止默認事件的兼容性寫法
var preventDefault = function(){
    if(event.preventDefault){
        event.preventDefault();
    }else{
        event.returnValue = false;
    }
};

//通用事件監聽對象
var Event = {
    addEvent: function(element,type,callback){
        if(element.addEventListener){
            element.addEventListener(type,callback,false);
        }else if(element.attachEvent){
            element.attachEvent('on' + type,callback);
        }
    },
    removeEvent: function(element,type,callback){
        if(element.removeEventListener){
            element.removeEventListener(type,callback,false);
        }else{
            element.detachEvent('on' + type, callback);
        }
    },
    getEvent: function(event){
        return event || window.event;
    },
    getTarget: function(event){
        return event.target || event.srcElement;
    },
    stopPropagation: function(event){
        if(event.stopPropagation){
            event.stopPropagation();
        }else{
            event.cancelBubble = true;
        }
    },
    preventDefault: function(event){
        if(event.preventDefault){
            event.preventDefault();
        }else{
            event.returnValue = false;
        }
    }
}