function Scrollable(el){
    el.step = 30;
    el.timeout = 130;
    el.scroll = 0;
    el.maxOffset = (el.getHeight() - el.up().getHeight());
    el.event = null;
    el.upper = function(){
        el.scroll = (el.scroll + el.step);
        if (el.scroll > el.maxOffset) 
            el.scroll = el.maxOffset;
        el.style.top = '-' + el.scroll + 'px';
    };
    el.lower = function(){
        el.scroll = (el.scroll - el.step);
        if (el.scroll < 0) 
            el.scroll = 0;
        el.style.top = '-' + el.scroll + 'px';
    };
    el.scrollUp = function(){
        el.event = window.setInterval(el.upper, el.timeout);
    };
    el.scrollDown = function(){
        el.event = window.setInterval(el.lower, el.timeout);
    };
    el.stop = function(){
        if (el.event) {
            window.clearInterval(el.event);
        }
    }
    el.relativize();
    return el;
};

function swEventInfo(id, mode){
    var info = $('event_info_' + id);
    if (mode) {
        info.setOpacity(0.8);
        info.show();
    }
    else {
        info.hide();
    }
}