title: $ajax success response print HTML page
body: <p>I have this code in my JS function, I need to call a PHP file "valiadte-attrib-form.php" this PHP script returns a variable. 
  This is my HTML page:</p>
  
  <pre><code> &lt;form method="post" id="form1" name="form1" action="&lt;?php echo $editFormAction; ?&gt;"&gt;
  
  &lt;script&gt;
     $(function() {   
       $('#form1').submit(function() {
          return validateForm();
       });
     });
  &lt;/script&gt;
  </code></pre>
  
  <p>This is my JS code:</p>
  
  <pre><code> function validateForm() {
      var form = $("#form1");
      $.ajax({
          context: form,
          type: 'GET',
          url: 'validate-attrib-form.php',
          data: params,
          success: function(response){  
              alert(response);
              result=response;  
              return result;
          }.bind(form)
      });
  </code></pre>
  
  <p>This is my PHP code:</p>
  
  <pre><code>    &lt;?php  
       echo "false";
  </code></pre>
  
  <p>But my problem is when a I see <strong>alert(response);</strong> I see full HTML codelike this:</p>
  
  <pre><code>&lt;!doctype html&gt;
  &lt;html lang="es"&gt;
  &lt;head&gt;  
     &lt;meta charset="iso-8859-1"/&gt; 
     &lt;meta name="viewport" content="width=device-width, minimum-scale=1, maximum-scale=1"/&gt;
  .....
  .....
  </code></pre>
  
  <p>What's wrong in my code? I need that <strong>alert(response)</strong> shows <strong>false</strong> not HTML code.
  Thanks for your help!</p>