function syncList(){} 

syncList.prototype.sync = function()
{
	for (var i=0; i < arguments.length-1; i++)	document.getElementById(arguments[i]).onchange = (function (o,id1,id2){return function(){o._sync(id1,id2);};})(this, arguments[i], arguments[i+1]);
	document.getElementById(arguments[0]).onchange();
}
syncList.prototype._sync = function (firstSelectId, secondSelectId)
{
	var firstSelect = document.getElementById(firstSelectId);
	var secondSelect = document.getElementById(secondSelectId);
	
	secondSelect.length = 0; 
	
	if (firstSelect.length>0)
	{
		if (firstSelect.selectedIndex == -1) firstSelect.options[0].selected = true; 

		var optionData = this.dataList[ firstSelect.options[firstSelect.selectedIndex].value ];
		for (var key in optionData || null) secondSelect.options[secondSelect.length] = new Option(optionData[key], key);
		if (secondSelect.length>0) secondSelect.options[0].selected = true;
		secondSelect.onchange && secondSelect.onchange();
	}
};