title: HTML Field Type Input Number Only or Letter Only Without JavaScript
body: <p>I create a form, where one field should only be filled with numbers.<p>
  I want that field can be filled <strong>only with numbers</strong> since entering input.<p>
  Like this example :</p>
  
  <p><a href="http://www.cambiaresearch.com/articles/39/how-can-i-use-javascript-to-allow-only-numbers-to-be-entered-in-a-textbox" rel="nofollow">How Can I Use Javascript to Allow Only Numbers to Be Entered in a TextBox?</a></p>
  
  <p>I've tried using <em>Regex</em>, but when I try to input is still able to enter letters.<p></p>
  
  <pre><code>&lt;input type="number" min="2" pattern="^[0-9]" class="andi_input required-entry" name="amount" id="amount" required title='Only Number' /&gt;
  </code></pre>
  
  <p><p>
  I want it when input to field and not after click the Submit button and the message appear and inform that the field can only be filled with numbers.<p>
  I also try to add <code>validate-number</code>, but the result is the same.<p>
  How, without javascript, so that the field can only be filled with numbers or letters?<p>
  Whether for this kind of case <strong>have to use JavaScript</strong> or is there another way without JavaScript?</p>