51help TIY
码：
<html> <body> <form id="myForm"> <select id="mySelect"> <option id="apple">Apple</option> <option id="orange">Orange</option> <option id="pineapple">Pineapple</option> <option id="banana">Banana</option> </select> </form> <p>The id of the form is: <script type="text/javascript"> document.write(document.getElementById("apple").form.id) </script> </p> </body> </html>
查看结果: