function showLAYER(idName){
  if(document.getElementById){
    document.getElementById(idName).style.visibility = 'visible'
  }else if(document.all){       //IE4—p
    document.all(idName).style.visibility   = 'visible'
  }else if(document.layers){    //NN4—p
    document.layers[idName].visibility     = 'show' 
  }
}

function hideLAYER(idName){
  if(document.getElementById){
    document.getElementById(idName).style.visibility = 'hidden'
  }else if(document.all){       //IE4—p
    document.all(idName).style.visibility   = 'hidden'
  }else if(document.layers){    //NN4—p
    document.layers[idName].visibility     = 'hide' 
  }
}