W3School TIY Editor
W3School 在线教程
改变方向
暗黑模式
运行代码
<!DOCTYPE html> <html> <head> <style> #myDiv { border-style: solid; } </style> </head> <body> <div id="myDiv">这是 div 元素。</div> <br> <button type="button" onclick="myFunction()">改变上边框的宽度</button> <script> function myFunction() { document.getElementById("myDiv").style.borderTopWidth = "thin"; } </script> </body> </html>