JS模拟鼠标点击按钮

var btn = document.querySelector("#su");
// 先要注册，然后触发，否则不行。
btn.addEventListener("click", function(e) {
console.log("simulate event");
}, false);
var event = document.createEvent("MouseEvents");
event.initMouseEvent('click',true,true,document.defaultView,0,0,0,0,0,false,false,false,false,0,null);
btn.dispatchEvent(event)

//模拟按住Shift的同时又按下A键：

var text = document.getElementsByTagNames("input")[0];
if (document.implementation.hasFeature("KeyboardEvents", 3.0) {
	var event = document.createEvent("KeyboardEvent");
	event.initKeyboardEvent("keydown", true, true, document.defaultView, "a", 0, "Shift", 0);
}