var scrolling = null;
  
     function scroll_up_a() {
         var a = document.getElementById('col-1');
  
         a.scrollTop = a.scrollTop - 5;
  
         scrolling_a = window.setTimeout(function() {
             scroll_up_a();
         }, 50);
     }
  
     function scroll_down_a() {
         var a = document.getElementById('col-1');
  
         a.scrollTop = a.scrollTop + 5;
  
        scrolling_a = window.setTimeout(function() {
             scroll_down_a();
         }, 50);
     }
  
     function stop_scroll_a() {
				window.clearTimeout(scrolling_a);
		}
		
		function scroll_up_b() {
         var b = document.getElementById('col-2');
  
         b.scrollTop = b.scrollTop - 5;
  
         scrolling_b = window.setTimeout(function() {
             scroll_up_b();
         }, 50);
     }
  
     function scroll_down_b() {
         var b = document.getElementById('col-2');
  
         b.scrollTop = b.scrollTop + 5;
  
        scrolling_b = window.setTimeout(function() {
             scroll_down_b();
         }, 50);
     }
  
     function stop_scroll_b() {
				window.clearTimeout(scrolling_b);
		}
		
		function scroll_up_c() {
         var c = document.getElementById('col-3');
  
         c.scrollTop = c.scrollTop - 5;
  
         scrolling_c = window.setTimeout(function() {
             scroll_up_c();
         }, 50);
     }
  
     function scroll_down_c() {
         var c = document.getElementById('col-3');
  
         c.scrollTop = c.scrollTop + 5;
  
        scrolling_c = window.setTimeout(function() {
             scroll_down_c();
         }, 50);
     }
  
     function stop_scroll_c() {
				window.clearTimeout(scrolling_c);
		}