fmpq.com
源代码：
点击运行
<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <title>Fmpq教程(fmpq.com)</title> </head> <body> <select size="6"> <option value="BMW">BMW</option> <option value="Mercedes">Mercedes</option> <optgroup id="myOptgroup" label="Swedish Cars"> <option value="volvo">Volvo</option> <option value="saab">Saab</option> <option value="koenigsegg">Koenigsegg</option> </optgroup> </select> <p>点击按钮返回选项组的 label 属性的值。</p> <p id="demo"></p> <button onclick="myFunction()">尝试一下</button> <script> function myFunction(){ var x = document.getElementById("myOptgroup").label; document.getElementById("demo").innerHTML=x; } </script> </body> </html>
运行结果