<!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> <script src="http://libs.baidu.com/jquery/1.10.2/jquery.min.js"></script> <script type="text/javascript"> var countdown=60; function settime(obj) { if (countdown == 0) { obj.removeAttribute("disabled"); obj.value="免费获取验证码"; countdown = 60; return; } else { obj.setAttribute("disabled", true); obj.value="重新发送(" + countdown + ")"; countdown--; } setTimeout(function() { settime(obj) } ,1000) } </script> <body> <input type="button" id="btn" value="免费获取验证码" onclick="settime(this)" /> </body> </html>
原文：http://www.cnblogs.com/itboy-2009/p/5276439.html