function findFirstSub(parentN,nName,cName) {
	var node = parentN.firstChild;
	if (node) {
		do {
			if (node.nodeName == nName && (cName==null || node.className==cName)) {
				return node;
			}
			node=node.nextSibling;
		} while (node!=null);
	}
	return null;
}

function findNextSub(lastSub,nName,cName) {
	if (!lastSub) {
		return null;
	}
	var node = lastSub.nextSibling;
	do {
		if ( node && node.nodeName == nName && (cName==null || node.className==cName)) {
			return node;
		}
    if (node) {
  		node=node.nextSibling;
    }
	} while (node !=null);
	return null;
}