function getPageOffsetLeft (el) {
	var ol=el.offsetLeft;
	while ((el=el.offsetParent) != null) { 
		ol += el.offsetLeft; 
	}
	return ol;
}
function getWindowOffsetLeft (el) {
	return getPageOffsetLeft(el)-document.body.scrollLeft;
}       
function getPageOffsetTop (el) {
	var ot=el.offsetTop;
	while((el=el.offsetParent) != null) {
		ot += el.offsetTop; 
	}
	return ot;
}
function getWindowOffsetTop (el) {
	return getPageOffsetTop(el)-document.body.scrollTop;
}
				
function i247_dropdown_show(head) {

	div_id = head.id + 'dd';

	if(document.getElementById) { // IE5+
		dd = document.getElementById(div_id);
		dd.style.left = getWindowOffsetLeft(head);
		dd.style.top = getWindowOffsetTop(head) + head.offsetHeight;
		dd.style.visibility = 'visible';
	}
	else
		head.href = '/catalogue.php';

}

function i247_dropdown_hide(head) {

	div_id = head.id + 'dd';
	if(document.getElementById) { // IE5+
		dd = document.getElementById(div_id);
		dd.style.visibility = 'hidden';
	}

}

function i247_dropdown_on(div) {
	div.style.visibility = 'visible';
}

function i247_dropdown_off(div) {
	div.style.visibility = 'hidden';
}