JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/dot-luv/jquery-ui.css">
<div id="new_prom" style="clear:both; padding:2px; border:1px solid red; margin:5px;">
<div>
  Codice <input type="text" id="cod_pro" name="cod_pro" class="short"> Sottocodice <input type="text" id="sotto_pro" name="sotto_pro" class="short"><br>
Nominativo<br>
<input type="text" id="nom_pro" name="nom_pro" class="long">
</div>
<div>
<div class="bt" id="bt_pro">INSERISCI</div> <div class="bt" id="resetta">RESET</div>
</div>

CSS

#resetta { border: solid 1px #ddd; }

JavaScript

$("#resetta").live('click', function() {
  $("#new_prom :text").val("");
});