title: $_FILES is empty
body: <p>I am using <a href="http://webdeveloperplus.com/jquery/ajax-multiple-file-upload-form-using-jquery/" rel="nofollow">Ajax file upload</a>
  bt $_FILES is always empty .</p>
  
  <p>this is my php page</p>
  
  <pre><code>    include('../../inc/functions.php');
      $allowdExt = array("mp4","flv");
      $uploaddir = '../../uploads/videos/';
      $filename = basename($_FILES['uploadv']['name']);
      echo "file: $uploaddir".$filename ;
      exit;
  
          $extension = getExtension($filename);
          $extension = strtolower($extension);
  
          if(!in_array($extension,$allowdExt)){
              $errors =1;
          }
          else
          {
              $file_name = MakeRandomChars().'.'.$extension ;
              $newname=$uploaddir.$file_name;
              $copied = move_uploaded_file($_FILES['uploadv']['tmp_name'], $newname);
              if (!$copied)
              {
                  $errors =1;
              }
          }
  
          if( $errors == 1){
              echo "0";
          }else{
              echo $file_name;
          }
  </code></pre>
  
  <p>and this is my jquery code :</p>
  
  <pre><code>$(function(){
      var btnUpload=$('#uploadVideo');
      var status=$('#status');
      new AjaxUpload(btnUpload, {
          action: 'pages/upload-video.php',
          name: 'uploadv',
          onSubmit: function(file, ext){
               if (! (ext &amp;&amp; /^(flv|mp4)$/.test(ext))){ 
                  status.text('Only Flv,Mp4 files are allowed');
                  return false;
  
              }
              $('#wait').fadeIn();
          },
          onComplete: function(file, response){
              status.text('');
              if(response != "0"){
                  $('#wait').fadeOut();
                  $('#videoIcon').fadeIn();
                  $('#status').attr('video',response);
              }
          }
      });     
  });
  </code></pre>