const myEvent = new CustomEvent(typeName, option)

• typeName ：DOMString 类型，表示创建事件的名称；
• option ： 可选配置项
  • detail：表示该事件中需要被传递的数据，在 EventListener 获取，默认 null
  • bubbles：表示该事件是否冒泡，默认 false
  • cancelable：表示该事件能否被取消。（影子DOM：Shadow DOM），默认 false

示例

// create custom events
const catFound = new CustomEvent('animalfound', {
  detail: {
    name: 'cat'
  }
});
const dogFound = new CustomEvent('animalfound', {
  detail: {
    name: 'dog'
  }
});

// add an appropriate event listener
obj.addEventListener('animalfound', (e) => console.log(e.detail.name));

// dispatch the events
obj.dispatchEvent(catFound);
obj.dispatchEvent(dogFound);

// "cat" and "dog" logged in the console**Polyfill（IE）**

Polyfill（IE）

/**
 * CustomEvent constructor polyfill for IE
 */
(function () {
    if (typeof window.CustomEvent === 'function') {
        // 如果不是IE
        return false;
    }

    var CustomEvent = function (event, params) {
        params = params || {
            bubbles: false,
            cancelable: false,
            detail: undefined
        };
        var evt = document.createEvent('CustomEvent');
        evt.initCustomEvent(event, params.bubbles, params.cancelable, params.detail);
        return evt;
    };

    CustomEvent.prototype = window.Event.prototype;

    window.CustomEvent = CustomEvent;
})();