Allow only numbers to be typed in a textbox
<blockquote>
  <p><strong>Possible Duplicate:</strong><br>
  <a href="http://stackoverflow.com/questions/995183/how-to-allow-only-numeric-0-9-in-html-inputbox-using-jquery">How to allow only numeric (0-9) in HTML  inputbox using jQuery?</a>  </p>
</blockquote>



<p>How to allow only numbers to be written in this textbox ?</p>

<pre><code>&lt;input type="text" class="textfield" value="" id="extra7" name="extra7"&gt;
</code></pre>
