/**************************************************

Simple DIV-Scroller for modern DOM-capable Browsers

Written by Sebastian Bechtold

sebastian_bechtold@web.de

You may use this script for whatever you want,
but please don't remove this note about its origin.

Thanks :)

**************************************************/

var scrollers = new Array();

function ScrollableLayer(id)
{
        this.contentLayer = document.getElementById(id);
        this.drawerline = document.getElementById('drawerline' + id);
        this.drawer = document.getElementById('drawer' + id);
        this.scrollframe = document.getElementById('scrollframe' + id);
        this.scrollHeight = this.contentLayer.offsetHeight - this.scrollframe.offsetHeight;
        this.contentLayer.style.position = 'relative';
        this.scrollframe.style.position = 'absolute';
}


function start_scroll(id, speed)
{
        scrollers[id] = new ScrollableLayer(id);

        new_id = id;
        new_speed = speed;

        scrollers[id].timer = window.setInterval("scroll(new_id, new_speed);",20);
}


function stop_scroll(id)
{
        window.clearInterval(scrollers[id].timer);
}


function scroll(id, speed)
{
        y_new = scrollers[id].contentLayer.offsetTop + speed;

        if (y_new <= 0 && y_new >= -scrollers[id].scrollHeight)
        {
                scrollers[id].contentLayer.style.top = y_new;

                if(scrollers[id].drawer && scrollers[id].drawerline)
                {
                        scrollers[id].drawer.style.top = scrollers[id].drawerline.offsetTop - (scrollers[id].drawerline.offsetHeight - scrollers[id].drawer.offsetHeight) * (y_new / scrollers[id].scrollHeight);
                }
        }
        else
        {
                height = 0;

                if (y_new < -scrollers[id].scrollHeight)
                {
                        height = scrollers[id].scrollHeight;
                }

                stop_scroll(id);
                start_scroll(id, height + y_new);
        }
}