title: Codeigniter form validation set rules to accept numbers and dashes
body: <p>I tried setting a rule in codeigniter form validation to accept input such as numbers and dashes. I read the Codeigniter documentation but it doesn't support such thing. Is there any way to write a custom function? Any help would be much appreciated.</p>
  
  <pre><code>$this-&gt;form_validation-&gt;set_rules('phone', 'Contact No.', 'numeric');
  </code></pre>