Day386:写一个通用的事件侦听器函数 about fe-interview HOT 3 OPEN

`export const myEvent = {
// 页面加载完成后
readEvent: function(fn: any){
if(fn === null || fn === undefined){
fn = document
}
let oldOnload: any = window.onload;
if(typeof window.onload !== "function"){
window.onload = fn
} else {
window.onload = function(){
oldOnload()
fn()
}
}
},
// 页面元素事件绑定
addEvent: function(element:any,type:any,handle:Function){
if(element.addEventListener){ // w3c
// 参数分别表示事件类型、需要执行的函数、是否捕捉
element.addEventListener(type,handle,false)
} else if(element.attachEvent){
element.attachEvent("on"+type,function(){
handle.call(element)
})
} else {
element["on"+type] = handle
}
},
removeEvent: function(element:any,type:any,handle:Function){
if(element.removeEventListener){
element.removeEventListener(type,handle,false)
} else if (element.detachEvent){
element.detachEvent("on"+type,handle)
} else {
element["on"+type] = null
}
},
stopPropagation: function(ev:any){
if(ev.stopPropagation){
ev.stopPropagation()
} else {
ev.cancelBubble = true
}
},
preventDefault: function(ev:any){
if(ev.preventDefault){
ev.preventDefault()
} else {
ev.returnValue = false
}
},
// 获取事件目标
getTarget: function(event:any){
return event.target || event.srcElement;
},
// 获取event对象的引用，取到事件的所有信息
getEvent: function(e:any){
let ev = e || window.event;
if(!ev){
let c = this.getEvent.caller
while(c){
ev = c.arguments[0]
if(ev && Event === ev.constructor){
break;
}
c = c.caller
}
}
return ev
}

}`

from fe-interview.

let eventUtils = {
            addEventListener:(ele,type,handler)=>{
                if(ele.addEventListener){
                    ele.addEventListener(type,handler)
                } else if(ele.attachEvent){
                    ele.attachEvent("on"+type,handler)
                } else {
                    ele['on'+type] = handler
                }
            },
            removeEventListener:(ele,type,handler)=>{
                if(ele.addEventListener){
                    ele.removeEventListener(type,handler)
                } else if(ele.attachEvent){
                    ele.detachEvent("on"+type,handler)
                } else {
                    ele['on'+type] = null
                }
            }
        }

from fe-interview.

`const EventUtils = {
// 分别使用dom0||dom2||IE方式 来绑定事件
// 添加事件
addEvent: function(element, type, handler) {
if (element.addEventListener) {
element.addEventListener(type, handler, false);
} else if (element.attachEvent) {
element.attachEvent("on" + type, handler);
} else {
element["on" + type] = handler;
}
},

// 移除事件
removeEvent: function(element, type, handler) {
if (element.removeEventListener) {
element.removeEventListener(type, handler, false);
} else if (element.detachEvent) {
element.detachEvent("on" + type, handler);
} else {
element["on" + type] = null;
}
},

// 获取事件目标
getTarget: function(event) {
return event.target || event.srcElement;
},

// 获取 event 对象的引用，取到事件的所有信息，确保随时能使用 event
getEvent: function(event) {
return event || window.event;
},

// 阻止事件（主要是事件冒泡，因为 IE 不支持事件捕获）
stopPropagation: function(event) {
if (event.stopPropagation) {
event.stopPropagation();
} else {
event.cancelBubble = true;
}
},

// 取消事件的默认行为
preventDefault: function(event) {
if (event.preventDefault) {
event.preventDefault();
} else {
event.returnValue = false;
}
}
};`

from fe-interview.