fmpq.com
源代码：
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<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Fmpq教程(fmpq.com)</title> <script> function displayResult(){ document.getElementById("mySelect").multiple=true; } </script> </head> <body> <form> <select id="mySelect" size="4"> <option>Apple</option> <option>Pear</option> <option>Banana</option> <option>Orange</option> </select> </form> <button type="button" onclick="displayResult()">允许多个选择</button> <p>按下Ctrl键来选择多个选项</p> </body> </html>
运行结果