源代码
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>编程字典</title> </head> <body> <select> <optgroup label="瑞典汽车"> <option value="volvo">沃尔沃</option> <option value="saab">萨博</option> </optgroup> <optgroup label="德国汽车" disabled> <option value="mercedes">奔驰</option> <option value="audi">奥迪</option> </optgroup> </select> </body> </html>
运行结果