function zindexLAYER(layName,zindex){
  if(document.layers)document.layers[layName].zIndex=zindex
  if(document.all)document.all(layName).style.zIndex=zindex
  if(document.getElementById)document.getElementById(layName).style.zIndex=zindex
}
function showLAYER(layName){
  if(document.layers)document.layers[layName].visibility='show'
  if(document.all)document.all(layName).style.visibility='visible'
  if(document.getElementById)document.getElementById(layName).style.visibility='visible'
}

function swtOnZ(layName){
	zindexLAYER('img0',0);zindexLAYER('img1',0);zindexLAYER('img2',0);zindexLAYER('img3',0)
	zindexLAYER(layName,2)
}