function showLAYER(layName){
    if(document.getElementById)
      document.getElementById(layName).style.visibility='visible'
    else if(document.all) 
      document.all(layName).style.visibility='visible'
    else if(document.layers) 
      document.layers[layName].visibility='show'
  }
function hideLAYER(layName){
    if(document.getElementById) 
      document.getElementById(layName).style.visibility='hidden'
    else if(document.all)
      document.all(layName).style.visibility='hidden'
    else if(document.layers)
      document.layers[layName].visibility='hide'
  }