title: validate form input type file type using jquery validate plugin
body: <p>the following code:
  script code</p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
  $(document).ready(function() {
      $("#formElem").validate({
  
          rules: {  
  
              dimage:{
                  minlength:200    
              }  
          },
  messages: {
  
  
               dimage:{
                 required: 'Please select the image!'  
              } ,
  
          }       
      });
  
  });
  &lt;/script&gt;
  </code></pre>
  
  <p>html code</p>
  
  <pre><code>&lt;form id="formElem" name="formElem" action="" method="post"&gt;
  
   &lt;input type="file" name="dimage" id="dimage" /&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>I'm using jquery validate.js file for client side validation. when i create a file with above code it's not showing any error message.</p>
  
  <p>How should i alert the error message when the user not selected the file?</p>