function showLayer(lyr) {
//   makeHistory(lyr);
   document.getElementById(currentLayer).className = 'hide';
   document.getElementById(lyr).className = 'show';
   currentLayer = lyr;
//   showTab(lyr.replace("tab","t_"));
}

function showTab(lyr) {
   document.getElementById(currentTab).className = 'taboff';
   document.getElementById(lyr).className = 'tabon';
   currentTab = lyr;
}