這個觸發(fā)事件不太明白，改了好久都沒能成功觸發(fā)，一直提示：Failed to execute 'dispatchEvent' on 'EventTarget': The event provided is null.事件綁定已經(jīng)成功了    window.onload = function() {             myAddEvent(document, "click", cons);            document.dispatchEvent("click");         }             function cons() {            console.log("232");         }                                      function myAddEvent(obj, ev, fn) { //對象，事件類型，函數(shù)             if(obj.addEventListener) { //高版本瀏覽器                 obj.addEventListener(ev, fn, false); //false 表示不捕獲             } else { //低版本瀏覽器  IE6-8                 obj.attachEvent('on' + ev, fn);             }         }