通用版事件侦听器函数

const eventUtils = {
			// 绑定事件
			addEvent(ele, type, handler){
				if(ele.addEventListener{
					ele.addEventListener(type, handler, false)
				}else if(ele.attachEvent){
					ele.attachEvent('on'+type, handler)
				}else{
					ele['on'+type] = handler
				}
			},
			// 移除事件
			removeEvent(ele, type, handler){
				if(ele.removeEventListener){
					ele.removeEventListener()
				}else if(ele.detachEvent){
					ele.detachEvent('on'+type, handler)
				}else{
					ele['on'+type] = null
				}
				
			},
			// 获取事件类型
			getEvent(event){
				return event || window.event
			},
			// 获取目标对象
			getTarget(event){
				return event.target || event.srcElement
			},
			// 阻止事件冒泡
			stopPropagation(event){
				if(event.stopPropagation){
					event.stopPropagation()
				}else{
					event.cancelBubble()
				}
			},
			// 阻止事件默认行为
			preventDefault(event){
				if(event.preventDefault){
					event.preventDefault()
				}else{
					event.retunValue = false
				}
			}
		}