var timer = null;
var step = 5;
var delay = 10;


function scrollDown()
{

    timer = setTimeout('scrollDown()', delay);
    
    a = document.getElementById('article');
    a.scrollTop += step;
}

function scrollUp()
{

    timer = setTimeout('scrollUp()', delay);
    
    a = document.getElementById('article');
    a.scrollTop -= step;
}

function release()
{

    clearTimeout(timer);clearTimeout   
}


function handle(delta)
{
    a = document.getElementById('article');
    a.scrollTop -= delta*20;

}
 
function wheel(event)
{
    var delta = 0;
    if (!event) /* For IE. */
    event = window.event;
    if (event.wheelDelta) 
    { /* IE/Opera. */
        delta = event.wheelDelta/120;
        if (window.opera)
            delta = -delta;
    } 
    else if (event.detail)
    { 
        delta = -event.detail/3;
    }
    if (delta)
        handle(delta);
}

function scroll_init()
{
    if (window.addEventListener)
        window.addEventListener('DOMMouseScroll', wheel, false);
    window.onmousewheel = document.onmousewheel = wheel;
}