<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>Title</title> <script> window.onload = function () { // 处理注册事件的兼容性问题 function addEventListener(ele, eventName, fn) { // 判断当前浏览器是否支持addEventListener if (ele.addEventListener) { ele.addEventListener(eventName, fn); // 第三个参数默认为false } else if(ele.attachEvent) { ele.attachEvent('on'+eventName, fn); } else { // 等价于ele.onclick = fn; ele['on' + eventName] = fn; } } var btn = document.getElementById('btn'); addEventListener(btn, 'click', function () { alert('你好'); }) } </script> </head> <body> <input type="button" value="点击" id="btn"> </body> </html>