var FINAL_DELAY = 0; // seconds to leave on screen after image is finished moving. Use 0 to leave open
var FINAL_POS = 85; // where image should stop moving (in px from top of window)
var SPEED = 5; // speed factor for movement, higher = faster

var noPx = document.childNodes ? 'px' : 0; // determine if 'px' must be added when specifiying position

function rmove(itm) {
	itm.style.top = -4000 + noPx;
	itm.style.display = 'none';
}
function move(itm,maxpos) {
	pos = parseInt(itm.style.top);
	if ( pos < maxpos ) {
		newpos = (pos + SPEED) + noPx;
		itm.style.top = newpos;
		setTimeout('move(document.getElementById(\'interstit\'),' + maxpos + ')',2);
	} else {
		if (FINAL_DELAY > 0) {
			setTimeout('rmove(document.getElementById(\'interstit\'))',FINAL_DELAY*1000);
		}
	}
}