<!-- A popup lecsúszásának sebessége -->
var div = 10;
var sliderEnabled = true;
function scrFol() {
	var ad = document.getElementById( 'slider' );
	var dPos = ( document.all ) ? document.body.scrollTop : window.pageYOffset;

	if ( ( dPos == 0 ) && ( document.all ) ) dPos = document.documentElement.scrollTop;

	dPos += 50;
	var cPos = parseInt( ad.style.top );
	if ( cPos == 0 ) cPos = dPos-1000;

	var posDif = dPos-cPos;

	if ( ( ad.style.display == 'none' ) && ( sliderEnabled ) ) ad.style.display = 'block';

	if ( posDif > 0 ) ad.style.top = (cPos+Math.ceil(posDif/div))+'px';
	else if ( posDif < 0 ) ad.style.top = (cPos+Math.floor(posDif/div))+'px';

	if ( sliderEnabled ) setTimeout( 'scrFol()', 20 );
}
function closeFollowSlider() {
	sliderEnabled = false;
	document.getElementById( 'slider' ).style.display = 'none';
}

<!-- A popup lecsúszásának késleltetése -->
setTimeout( 'scrFol()', 500 );