function posun(){
		var div_form = document.getElementById('reklama');
		var pos = document.documentElement.scrollTop;
		var end = document.getElementById('content').clientHeight - 300;
		if(pos < 16) pos = 16;
		if(pos > end) pos = end;
		div_form.style.padding = pos + 'px 0px 0px 0px';
	}

window.onscroll = posun;