var currMap;

function toggleMap( newMapName)
{
    if( currMap == null)
        currMap = window.document.all( 'polska', 0);

    var newMap = window.document.all( newMapName, 0);

    if( newMap != null)
    {
        if( currMap != newMap)
            currMap.style.display = 'none';

        newMap.style.display = 'block';
        currMap = newMap;
    }
}