三种自定义事件形式

          var event = new Event('myEvent');        document.addEventListener("myEvent", function (e) {            console.log(e);        })        document.dispatchEvent(event);           var event = new CustomEvent('myEvent', { 'dataName': "ss" });        document.addEventListener("myEvent", function (e) {            console.log(e);        })        document.dispatchEvent(event);        document.body.addEventListener("veb", function (e) {            alert(e.eventType)        })        var event = document.createEvent('HTMLEvents');        // initEvent承受3个参数:        // 事件类型,是否冒泡,是否阻止浏览器的默认行为        event.initEvent("veb", false, true);        //通过eventType传递事件信息        event.eventType = "I love Veblen"        //触发document上绑定的click事件        document.body.dispatchEvent(event);