function scroll_banner () {
	
	var a = 1500;
	var b = document.getElementById('skyscraper');
	
	var c = 0;
	
	try {
		c = document.documentElement.scrollTop;
	} catch (e) {
		c = document.body.scrollTop + 7;
	}

	if ( c < a ) {
		b.style.posTop = c;
		b.style.top = '' + c + 'px';
	}
}