function get_scroll_xy() {
	var scroll_x = 0, scroll_y = 0;
	if(typeof(window.pageYOffset) == 'number') {
		//Netscape compliant
		scroll_y = window.pageYOffset;
		scroll_x = window.pageXOffset;
	} else if(document.body && (document.body.scrollLeft || document.body.scrollTop)) {
		//DOM compliant
		scroll_y = document.body.scrollTop;
		scroll_x = document.body.scrollLeft;
	} else if(document.documentElement && (document.documentElement.scrollLeft || document.documentElement.scrollTop)) {
		//IE6 standards compliant mode
	    scroll_y = document.documentElement.scrollTop;
	    scroll_x = document.documentElement.scrollLeft;
	}
	return[scroll_x, scroll_y];
}

function layer_over(_value, _eventx, _eventy) {
	var scroll_xy = new Array(2);
	scroll_xy = get_scroll_xy();
	scroll_left = scroll_xy[0];
	scroll_top = scroll_xy[1];
	var pop_up = document.getElementById(_value);
	x = _eventx + scroll_left;
	y = _eventy + scroll_top - 150;
	pop_up.style.top = y + 'px';
	pop_up.style.left = x + 'px';
	pop_up.style.visibility = 'visible';
}

function layer_out(_value) {
	document.getElementById(_value).style.visibility = 'hidden';
}