Question

js 有没有办法 判断一个dom元素是否已经绑定了某个事件

Answer 1

js 有办法 判断一个dom元素是否已经绑定了某个事件！
代码如下：

/*
* 事件注册
* @param Element ele
* @param String eventType
* @param Function fn
* @param Boolean isRepeat
* @param Boolean isCaptureCatch
* @return undefined
*/
function loginEvent(ele , eventType , fn , isRepeat , isCaptureCatch){
if (ele == undefined || eventType === undefined || fn === undefined) {
throw new Error('传入的参数错误！');
}

if (typeof ele !== 'object') {
throw new TypeError('不是对象！');
}

if (typeof eventType !== 'string') {
throw new TypeError('事件类型错误！');
}

if (typeof fn !== 'function') {
throw new TypeError('fn 不是函数！');
}

if (isCaptureCatch === undefined || typeof isCaptureCatch !== 'boolean') {
isCaptureCatch = false;
}

if (isRepeat === undefined || typeof isRepeat !== 'boolean') {
isRepeat = true;
}

if (ele.eventList === undefined) {
ele.eventList = {};
}

if (isRepeat === false) {
for (var key in ele.eventList)
{
if (key === eventType) {
return '该事件已经绑定过！';
}
}
}

// 添加事件监听
if (ele.addEventListener) {
ele.addEventListener(eventType , fn , isCaptureCatch);
} else if (ele.attachEvent) {
ele.attachEvent('on' + eventType , fn);
} else {
return false;
}

ele.eventList[eventType] = true;
}