function showHideLayers(div1,extra1,sh1,div2,extra2,sh2,div3,extra3,sh3,div4,extra4,sh4){

 if(sh1=='show') document.getElementById(div1).style.display='block';
 else document.getElementById(div1).style.display='none';
 if(sh2=='show') document.getElementById(div2).style.display='block';
 else document.getElementById(div2).style.display='none';
 if(sh3=='show') document.getElementById(div3).style.display='block';
 else document.getElementById(div3).style.display='none';
 if(sh4=='show') document.getElementById(div4).style.display='block';
 else document.getElementById(div4).style.display='none';
}

function setCurrent(elem_id){
  for(i=1;i<5;i++){
    if(i==elem_id)   document.getElementById('current_tab_'+i).className="underline";
    else  document.getElementById('current_tab_'+i).className="normal";
  }
 
  
}