Código HTML:
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Titulo</title> <link type="text/css" href="Librerias/jquery-ui-1.8.13.custom.css" rel="Stylesheet" /> <script type="text/javascript" src="Librerias/jquery-1.5.1.min.js"></script> <script type="text/javascript" src="Librerias/jquery-ui-1.8.13.custom.min.js"></script> <script type="text/javascript"> $(document).ready(function() { $("input:submit", ".Campo").button(); $('.Campo').change(function() { $('#botonsumit').removeAttr("disabled"); }); }); </script> </head> <body> <div class="Campo"> <input type="text" id="texto" value=""/> <input type="submit" id="botonsumit" value="A submit button" disabled="true"/> </div> </body> </html>