W3School TIY Editor
W3School 在线教程
改变方向
暗黑模式
运行代码
<html> <head> <script type="text/javascript"> function alertOptionId() { var x=document.getElementById("mySelect").selectedIndex; alert(document.getElementsByTagName("option")[x].id); } </script> </head> <body> <form> Select your favorite fruit: <select id="mySelect"> <option id="apple">Apple</option> <option id="orange">Orange</option> <option id="pineapple">Pineapple</option> <option id="banana">Banana</option> </select> <br /><br /> <input type="button" onclick="alertOptionId()" value="Alert id"> </form> </body> </html>