<!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>