Voilà mon code :
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Document sans nom</title>
<style type="text/css">
<!--
#Layer1 {
position:absolute;
left:167px;
top:25px;
width:194px;
height:128px;
z-index:2;
}
-->
</style>
</head>
<script language="JavaScript" type="text/JavaScript">
<!--
function MM_reloadPage(init) { //reloads the window if Nav4 resized
if (init==true) with (navigator) {if ((appName=="Netscape" )&&(parseInt(appVersion)==4)) {
document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
function MM_findObj(n, d) { //v4.01
var p,i,x; if(!d) d=document; if((p=n.indexOf("?" ))>0&&parent.frames.length) {
d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);}
if(!(x=d[n])&&d.all) x=d.all[n]; for (i=0;!x&&i<d.forms.length;i++) x=d.forms[i][n];
for(i=0;!x&&d.layers&&i<d.layers.length;i++) x=MM_findObj(n,d.layers[i].document);
if(!x && d.getElementById) x=d.getElementById(n); return x;
}
function MM_showHideLayers() { //v6.0
var i,p,v,obj,args=MM_showHideLayers.arguments;
for (i=0; i<(args.length-2); i+=3) if ((obj=MM_findObj(args[i]))!=null) { v=args[i+2];
if (obj.style) { obj=obj.style; v=(v=='show')?'visible'
v=='hide')?'hidden':v; }
obj.visibility=v; }
}
//-->
</script>
</head>
<body>
<div id="LeCalque" style="position:absolute; left:28px; top:97px; width:243px; height:179px; z-index:1; background-color: #FF9900; layer-background-color: #FF9900; border: 1px none #000000;">Mon calque</div>
<p><a href="javascript:;" onClick="MM_showHideLayers('LeCalque','','show')">Montrer</a> | <a href="javascript:;" onClick="MM_showHideLayers('LeCalque','','hide')">Cacher</a></p>
</body>
</html>