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

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