W3School TIY Editor
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<!DOCTYPE html> <html> <head> <style> h1 { counter-increment: section; } h1:before { content: "Section " counter(section) " "; } </style> </head> <body> <h1>HTML 教程</h1> <h1 id="myH1">CSS 教程</h1> <h1>JavaScripts 教程</h1> <p>点击“试一试”按钮可更改第二个 H1 元素的 counterIncrement：</p> <button onclick="myFunction()">试一试</button> <script> function myFunction() { document.getElementById("myH1").style.counterIncrement = "subsection"; } </script> </body> </html>