微语 微语:代码适合中午敲,早晚出BUG

js三种注册事件 JavaScript

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>
    <body>
        <button class="btn">1</button>
        <button onclick="btn2()">2</button>
        <button class="btn3">3</button>
        <script>
            const Btn = document.querySelector(".btn")
            Btn.onclick=function(){
                console.log("在DOM上注册事件")
            }
            function btn2(){
                console.log("自定义函数")
            }

            const Btn3 = document.querySelector(".btn3")
            Btn3.addEventListener("click",function(){
                console.log("W3C标准注册事件")
            })
        </script>
    </body>
</html>