var speed = 2;
var MIN_SPEED = 2;
var MAX_SPEED = 14;
var crossobj = "";
var contentheight = 0;

function movedown(){
    if(document.getElementById)
        crossobj = document.getElementById("nav_content_afp");
    else
        crossobj = document.all.content;

    contentheight = crossobj.offsetHeight;
    
    if ( parseInt(crossobj.style.top) >= (contentheight*(-1)+200) ) {
        crossobj.style.top = (parseInt(crossobj.style.top) - speed) + "px";
    }
    
    movedownvar = setTimeout("movedown()",100);
}

function moveup(){
    if(document.getElementById)
        crossobj = document.getElementById("nav_content_afp");
    else
        crossobj = document.all.content;
    
    if (parseInt(crossobj.style.top)<=0)
        crossobj.style.top = (parseInt(crossobj.style.top) + speed) + "px";
    
    moveupvar = setTimeout("moveup()",100);
}