gistfile1.js

success: function(data) {

  if(data == 'error') {
  } else {
    var span = $('<span class="label label-success"><strong>Success</strong></span>');
    $this.closest('tr').find('td').first().append( span );
    // after 3 seconds...
    setTimeout(function(){
      // hide the span, once that's done, remove it
      span.hide( 'normal', function() { 
        span.remove();        
      }); 
    }, 3000);	
  }						
}