var scrollbar = new Control.ScrollBar('scrollbar_content','scrollbar_track');  
   
 $('scroll_down_50').observe('click',function(event){  
     scrollbar.scrollBy(-50);  
     event.stop();  
 });  
   
 $('scroll_up_50').observe('click',function(event){  
     scrollbar.scrollBy(50);  
    event.stop();  
 });  
   
 $('scroll_top').observe('click',function(event){  
     scrollbar.scrollTo('top');  
     event.stop();  
 });  
   
 $('scroll_bottom').observe('click',function(event){  
     //to animate a scroll operation you can pass true  
     //or a callback that will be called when scrolling is complete  
     scrollbar.scrollTo('bottom',function(){  
         if(typeof(console) != "undefined")  
             console.log('Finished scrolling to bottom.');  
     });  
     event.stop();  
 });  
   
 $('scroll_second').observe('click',function(event){  
     //you can pass a number or element to scroll to  
     //if you pass an element, it will be centered, unless it is  
     //near the bottom of the container  
     scrollbar.scrollTo($('second_subhead'));  
     event.stop();  
 });  
   
 $('scroll_third').observe('click',function(event){  
     //passing true will animate the scroll  
     scrollbar.scrollTo($('third_subhead'),true);  
     event.stop();  
 });  
   
 $('scroll_insert').observe('click',function(event){  
     $('scrollbar_content').insert('<p><b>Inserted: ' + $('repeat').innerHTML + '</b></p>');  
     //you only need to call this if ajax or dom operations modify the layout  
    //this is automatically called when the window resizes  
     scrollbar.recalculateLayout();  
     event.stop();  
 });