title: Codeigniter form validation greater than field one and less than field two
body: <p>How to create form validation in Codeigniter base on other field, for example I have two field (field_one, and field_two) where field_one is must be less_than field_two and field_to must be greater_than field_one.</p>
  
  <pre><code>$this-&gt;form_validation-&gt;set_rules('field_one', 'Field One', 'less_than[field_two]');
  
  $this-&gt;form_validation-&gt;set_rules('field_two', 'Field Two', 'greater_than[field_one]');
  </code></pre>
  
  <p>my code is doesn't work, the error always displaying</p>
  
  <p>'Field two must be greater than field one'</p>
  
  <p>but I input the right way,</p>
  
  <p>field one 1
  field two 4</p>
  
  <p>how to solve this? Plz help me!</p>