title: grey out submit button until form filled out
body: <p>I have the following form:</p>
  
  <pre><code> &lt;form action="http://www.tahara.es/contact/subscribe.php" method="post" id="subscribe" name="subscribe"&gt;
        &lt;input type="hidden" name="action" value="subscribe"&gt;
        &lt;label&gt;NAME:&lt;/label&gt;
        &lt;input type="text" name="name" class="Textbox" id="sub_first_name"&gt;
        &lt;label&gt;EMAIL:&lt;/label&gt;
        &lt;input type="text" name="email" class="Textbox" id="sub_email"&gt;
        &lt;input type="submit" name="button" id="button" value="Subscribe" /&gt;
  </code></pre>
  
  <p>I would like to grey out the <code>submit</code> button until both fields in the form have been filled out. I guess jquery would do the trick?</p>
  
  <p>How can I do this, and where should I place the script? </p>