function showLAYER(idName){ 
if(document.getElementById)//NN6,Mozilla,IE5用
document.getElementById(idName).style.visibility = 'visible' 
else if(document.all)//IE4用
document.all(idName).style.visibility = 'visible' 
else if(document.layers)//NN4用
document.layers[idName].visibility = 'show' 
}

function hideLAYER(idName){ 
  if(document.getElementById) //NN6,Mozilla,IE5用
    document.getElementById(idName).style.visibility
                                           = 'hidden' 
    
  else if(document.all)       //IE4用
    document.all(idName).style.visibility   = 'hidden' 
    
  else if(document.layers)    //NN4用
    document.layers[idName].visibility     = 'hide' 
}