<html> <head> <script type="text/javascript"> window.onload = function() { var sel = document.getElementById("mySelect"); if(sel&&sel.addEventListener){ sel.addEventListener(‘change‘,function(e){ var ev = e||window.event; var target = ev.target||ev.srcElement; alert(target.value); },false) } } </script> </head> <body> <form> Select your favorite fruit: <select id="mySelect"> <option value="20">Apple</option> <option value="30">Orange</option> <option value="40">Pineapple</option> <option value="50">Banana</option> </select> <br /><br /> <input type="button" value="Alert index of selected option"> </form> </body> </html>
原文：http://www.cnblogs.com/chenmiaosong/p/7755017.html