var speed_Nav=2;

var crossobj_Nav = document.getElementById ? document.getElementById("contentscroll_Nav") : document.all.contentscroll;

var contentheight_Nav = crossobj_Nav.offsetHeight;

function movedown_Nav(){
    if (window.moveupvar_Nav)
        clearTimeout(moveupvar_Nav);

    if (parseInt(crossobj_Nav.style.top) >= (contentheight_Nav * (-1) + 100))
    crossobj_Nav.style.top = parseInt(crossobj_Nav.style.top) - speed_Nav + "px";
        
    movedownvar_Nav = setTimeout("movedown_Nav()", 20);
}

function moveup_Nav(){
    if (window.movedownvar_Nav)
        clearTimeout(movedownvar_Nav);

    if (parseInt(crossobj_Nav.style.top) <= 0)
    crossobj_Nav.style.top = parseInt(crossobj_Nav.style.top) + speed_Nav + "px";
        
    moveupvar_Nav = setTimeout("moveup_Nav()", 20);
}

function stopscroll_Nav(){
    if (window.moveupvar_Nav) 
    clearTimeout(moveupvar_Nav);
if (window.movedownvar_Nav)
    clearTimeout(movedownvar_Nav);
}

function movetop_Nav()
{
    stopscroll_Nav();
    crossobj_Nav.style.top = 0 + "px";
}

function getcontent_height_Nav()
{
    contentheight_Nav = crossobj_Nav.offsetHeight;
}

window.onload = getcontent_height_Nav;