W3School TIY Editor
W3School 在线教程
改变方向
暗黑模式
运行代码
<html> <head> <style type="text/css"> p { border: thin dotted #FF0000; } </style> <script type="text/javascript"> function changeBorder() { document.getElementById("p1").style.borderLeft="thick solid #0000FF"; } </script> </head> <body> <input type="button" onclick="changeBorder()" value="Change left border" /> <p id="p1">This is a paragraph</p> </body> </html>