/* 
  ------------------------------------
  Tab script
  ------------------------------------
*/

last_tab = 'tab_area_01';
function show(layerName) { 
document.getElementById(layerName).style.display = '';
} 

function hide(layerName) { 
document.getElementById(layerName).style.display = 'none';
} 

function show_next(tab_name) {
hide(last_tab);
show(tab_name);
last_tab=tab_name;
}