Código HTML:
Ver original<!DOCTYPE HTML>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script> <script type="text/javascript"> $(function(){
$("form").submit(function(){
$("input[type=submit]",this).prop("disabled",true);
return false;
});
})
<input type="submit" value="Enviar"/>