这个 onkeydown 事件属性在用户按下键盘上的任意键时起作用。支持的标签：它支持所有 HTML 元素，除了- <基地> <头> </strong></li> <li> <strong><元></strong></li> <li> <strong><参数></strong></li> <li> <strong><脚本></strong></li> <li> <strong><样式></strong></li> <li> <strong><标题></strong></li> </ul> <p><strong>句法：</strong> </p> <div class="hcb_wrap"> <pre class="prism line-numbers lang-html" data-lang="HTML"><code class="replace"><element onkeydown = "script"></code></pre> </div> <p><strong>属性值：</strong>该属性包含单值<i>脚本</i>，当从键盘按下任何键时该脚本起作用。<br/><strong>支持的标签：</strong>除 <base>、<bdo>、<br>、<head>、<html>、<iframe>、<meta>、<param>、<script>、<style> 之外的所有 HTML 元素都支持它, 和 <title>。<br/><strong>例子：</strong></p> <div> <h5 class="code">html</h5> <div class="hcb_wrap"> <pre class="prism line-numbers lang-html" data-lang="HTML"><code class="replace"><!DOCTYPE html> <html> <head> <title> HTML | onkeydown Event Attribute </title> <style> h1 { text-align: center; color: green; } h2 { text-align: center; } input[type=text] { width: 100%; padding: 12px 20px; margin: 8px 0; box-sizing: border-box; font-size: 24px; color: white; } p { font-size: 20px; } </style> </head> <body> <h1>GeeksforGeeks<h1> <h2>onkeyup Event Attribute</h2> <p>Release the key to set a green background color.</p> <input type="text" id="demo" onkeydown="keydownFunction()" onkeyup="keyupFunction()"> <script> function keyupFunction() { document.getElementById("demo").style.backgroundColor = "blue"; } function keydownFunction() { document.getElementById("demo").style.backgroundColor = "green"; } </script> </body> </html></code></pre> </div> <p></p> <hr/> </div> <p><strong>输出：</strong><br/><strong>按下按键：</strong> </p> <p><img alt="按键按下" class="img-fluid" src="https://mangodoc.oss-cn-beijing.aliyuncs.com/geek8geeks/HTML_%7C_onkeydown_Event_Attribute_0.jpg"/></p> <p></p> <div class="_ap_apex_ad" id="d6f45c53-ff16-4cc5-8b91-eb6ee7037116" style="min-height:280px"></div> <p></p> <p><strong>释放密钥：</strong> </p> <p><img alt="onkeydown2" class="img-fluid" src="https://mangodoc.oss-cn-beijing.aliyuncs.com/geek8geeks/HTML_%7C_onkeydown_Event_Attribute_1.jpg"/></p> <p><strong>支持的浏览器：</strong> <i>onkeydown</i>事件属性支持的浏览器如下：</p> <ul> <li>铬合金</li> <li>IE浏览器</li> <li>火狐</li> <li>苹果浏览器</li> <li>歌剧</li> </ul> <div class="_ap_apex_ad" id="82d2079a-8120-480f-9fc7-5cda825d56e7" style="min-height:280px"></div> <p></p></div> </article> </div> </div> </div> </div> </div> <footer> <div class="bg-white text-center pb-1"> <p class="text-body-tertiary pt-3 lh-lg text-opacity-50" id="footer-text">Copyright © 2020 - 2024 版权所有 <br> <a href="https://beian.miit.gov.cn/" target="_blank" class="text-opacity-50 text-body-tertiary mt-1 mb-1">蜀ICP备20006366号-1</a> <br> Made with ❤️ in Chengdu </p> </div> </footer> <!-- 引入Bootstrap JavaScript库 --> <script src="https://unpkg.com/bootstrap@5.3.0-alpha1/dist/js/bootstrap.bundle.min.js" crossorigin="anonymous"></script> <!-- 引入Meilisearch搜索相关的JavaScript库 --> <script src="https://cdn.jsdelivr.net/npm/@meilisearch/instant-meilisearch/dist/instant-meilisearch.umd.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/instantsearch.js@4"></script> <script src="https://imangodoc.com/static/javascript/meili_custom.js"></script> <!-- 引入prismjs代码高亮相关的JavaScript库 --> <script src="https://cdn.jsdelivr.net/npm/prismjs@1.29.0/components/prism-core.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/prismjs@1.29.0/plugins/toolbar/prism-toolbar.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/prismjs@1.29.0/plugins/autoloader/prism-autoloader.min.js"></script> <script src="https://cdn.jsdelivr.net/npm/prismjs@1.29.0/plugins/copy-to-clipboard/prism-copy-to-clipboard.min.js"></script> </body> </html>