// Create a self-invoking anonymous function. That way,   
 // we're free to use the jQuery dollar symbol anywhere within.  
 (function($) {  
   
 // We name our plugin "newscroll". When creating our function,   
 // we'll allow the user to pass in a couple of parameters.  
 $.fn.newsScroll = function(options) {  
       
     // For each item in the wrapped set, perform the following.   
     return this.each(function() {     
         
         var  
           // Caches this - or the ul widget(s) that was passed in.  
           //  Saves time and improves performance.  
           $this = $(this),   
             
           // If the user doesn't pass in parameters, we'll use this object.   
           defaults = {  
             speed: 400, // How quickly should the items scroll?  
             delay: 3000, // How long a rest between transitions?  
             list_item_height: $this.children('li').outerHeight() // How tall is each list item? If this parameter isn't passed in, jQuery will grab it.  
          },  
           // Create a new object that merges the defaults and the   
           // user's "options".  The latter takes precedence.  
           settings = $.extend({}, defaults, options);  
            
       // This sets an interval that will be called continuously.  
       setInterval(function() {  
             // Get the very first list item in the wrapped set.  
             $this.children('li:first')  
                     // Animate it  
                     .animate({   
                         marginTop : '-' + settings.list_item_height, // Shift this first item upwards.  
                        opacity: 'hide' }, // Fade the li out.  
                          
                        // Over the course of however long is   
                        // passed in. (settings.speed)  
                        settings.speed,   
                          
                        // When complete, run a callback function.  
                        function() {  
                           
                         // Get that first list item again.   
                             $this.children('li:first')  
                                  .appendTo($this) // Move it the very bottom of the ul.  
                                    
                                  // Reset its margin top back to 0. Otherwise,   
                                  // it will still contain the negative value that we set earlier.  
                                  .css('marginTop', 0)   
                                  .fadeIn(300); // Fade in back in.  
                       }  
                   ); // end animate  
       }, settings.delay); // end setInterval  
       });  
 }  
   
 })(jQuery);