键盘事件监听与文本输入-优快云博客

效果如下

代码如下：
首先看目录

//index.html
<!DOCTYPE html>
<html lang="zh-CN">
<head>
  <meta charset="UTF-8">
  <title>KeyboardEvent.key</title>
  <link type="text/css" rel="stylesheet" href="style.css">
  <script src="main.js" defer></script>
</head>

<body>
  <div class="flex flex-left">
    <textarea rows="5" id="test-target"></textarea>
    <button id="btn-clear-console">清空控制台</button>
  </div>
  <div class="flex flex-right">
    <div id="console-log"></div>
  </div>
</body>
</html>

//main.js
//输入的内容
const textarea = document.getElementById('test-target');
//右边
const consoleLog = document.getElementById('console-log');
//点击按钮
const btnClearConsole = document.getElementById('btn-clear-console');

function logMessage(message) {
    //动态创建p标签，存储textarea.addEventListener中监听的内容
  const p = document.createElement('p');
  p.appendChild(document.createTextNode(message));
  consoleLog.appendChild(p);
}

textarea.addEventListener('keydown', e => {
  if (!e.repeat)
    logMessage(`第一个 keydown 事件。key 属性的值为"${e.key}"`);
  else
    logMessage(`keydown 事件重复。key 属性的值为"${e.key}"`);
});
  
textarea.addEventListener('beforeinput', e => {
  logMessage(`beforeinput 事件。你准备输入"${e.data}"`);
});
  
textarea.addEventListener('input', e => {
  logMessage(`input 事件。你刚刚输入了"${e.data}"`);
});
  
textarea.addEventListener('keyup', e => {
  logMessage(`keyup 事件。key 属性的值为"${e.key}"`);
});

  //点击 btnClearConsole移除内容 这里是移除右边consoleLog中的元素
btnClearConsole.addEventListener('click', e => {
  let child = consoleLog.firstChild;
  while (child) {
    consoleLog.removeChild(child);
    child = consoleLog.firstChild;
  }
});

//style.css
body {
    -webkit-display: flex;
    display: flex;
}
    
.flex {
    padding-left: 20px;
    padding-right: 20px;
}
    
.flex-left {
    flex: 1;
    flex-grow: 1;
    -webkit-flex: 1;
    -webkit-flex-grow: 1;
}
    
.flex-right {
    flex: 2;
    flex-grow: 2;
    -webkit-flex: 2;
    -webkit-flex-grow: 2;
}
    
#test-target {
    display: block;
    width: 100%;
    margin-bottom: 10px;
    resize: none;
}

#console-log {
    overflow: auto;
}

转载于:https://www.cnblogs.com/smart-girl/p/10717771.html