function LayerShow(strName) {
	if ((document.all[strName]!='undefined') && (document.all[strName]!=null)) {
		document.all[strName].className = 'show';
	}
}

function LayerHide(strName) {
	if ((document.all[strName]!='undefined') && (document.all[strName]!=null)) {
		document.all[strName].className = 'hidden';
	}
}

function LayerHideAll()
{
  LayerHide('Layer1');
  LayerHide('Layer2');
  LayerHide('Layer3');
  LayerHide('Layer4');
}