// JavaScript Document
var scrolling = null;
 
    function scroll_up(id) {
        var d = document.getElementById(id);
 
        d.scrollTop = d.scrollTop - 5;
 
        scrolling = window.setTimeout(function() {
            scroll_up(id);
        }, 100);
    }
 
    function scroll_down(id) {
        var d = document.getElementById(id);
 
        d.scrollTop = d.scrollTop + 5;
 
        scrolling = window.setTimeout(function() {
            scroll_down(id);
        }, 100);
    }
 
    function stop_scroll(id) {
        window.clearTimeout(scrolling);
    }