解释 JavaScript 中的按键事件?

javascriptweb developmentobject oriented programming更新于 2025/8/21 17:16:17

每当用户与键盘交互时，就会发生按键事件。主要有三种按键事件类型:keydown、keypress 和 keyup。

事件	描述
Onkeydown	当用户按下某个键时触发此事件
Onkeypress	当用户按下该键时触发此事件
Onkeyup	当用户释放该键时触发此事件。

以下是 JavaScript 中按键事件的代码 −

示例

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
   body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
   }
   .result {
      font-size: 18px;
      color: blueviolet;
      font-weight: 500;
   }
</style>
</head>
<body>
<h1>Key-events in JavaScript</h1>
<div class="result"></div>
<h3>Press or release key to see the keyevent fired</h3>
<script>
   let resEle = document.querySelector(".result");
   document.body.addEventListener("keydown", () => {
      resEle.innerHTML = "keydown event is being fired <br>";
   });
   document.body.addEventListener("keyup", () => {
      resEle.innerHTML = "keyup event is being fired";
   });
   document.body.addEventListener("keypress", () => {
      resEle.innerHTML += "keypress event is being fired";
   });
</script>
</body>
</html>