function OnChangeCountry(oForm, sCountrySelectID, sStateSelectID, sStateTextID)
{
	// optional function argument
	var bAusDefault = true;
	if( arguments.length > 4 )
	  bAusDefault = arguments[4];

	var oCountrySelect;
	var oStateSelect;
	var oStateText;

	oCountrySelect = oForm.elements[ sCountrySelectID ];
	oStateSelect = oForm.elements[ sStateSelectID ];
	oStateText = oForm.elements[ sStateTextID ];

	var bShowAusStates = false;
	if( oCountrySelect.selectedIndex != -1 )
	{
		if( oCountrySelect.options[oCountrySelect.selectedIndex].value == "AU" )
		{
			bShowAusStates = true;
		}
		else if( bAusDefault == true && oCountrySelect.selectedIndex == 0 )
		{
			bShowAusStates = true;
		}
	}

	if( bShowAusStates )
	{
		oStateSelect.style.display = ""; //show
		oStateText.style.display = "none"; //hide
	}
	else
	{
		oStateSelect.style.display = "none"; //hide
		oStateText.style.display = ""; //show
	}
}