W3School TIY Editor
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<!DOCTYPE html> <html> <head> <meta name="viewport" content="width=device-width, initial-scale=1"> <style> .alert { padding: 20px; background-color: #f44336; color: white; } .closebtn { margin-left: 15px; color: white; font-weight: bold; float: right; font-size: 22px; line-height: 20px; cursor: pointer; transition: 0.3s; } .closebtn:hover { color: black; } </style> </head> <body> <h2>警告消息</h2> <p>点击“x”符号以关闭警告消息。</p> <div class="alert"> <span class="closebtn" onclick="this.parentElement.style.display='none';">×</span> <strong>危险!</strong> 表示一个危险或潜在的负面行为。 </div> </body> </html>