V'là un exemple, suffit d'adapter à ton cas
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<html>
<head>
<title>Sans titre</title>
<script language="JavaScript">
<!--
function na_show_layer(lname)
{
if (na_show_layer.arguments.length <= 1) { // don't delete, backword compatibility
if(document.getElementById) {
document.getElementById(lname).style.visibility = 'visible';
} else if(document.layers) {
document.layers[lname].visibility = 'show'
} else if(document.all)
document.all(lname).style.visibility = 'visible'
} else {
if(document.getElementById) {
document.getElementById(lname).style.visibility = 'hidden';
} else if(document.layers) {
document.layers[lname].visibility = 'hide'
} else if(document.all)
document.all(lname).style.visibility = 'hidden'
}
}
function na_hide_layer(lname)
{
if(document.getElementById) {
document.getElementById(lname).style.visibility = 'hidden';
} else if(document.layers) {
document.layers[lname].visibility = 'hide'
} else if(document.all)
document.all(lname).style.visibility = 'hidden'
}
// -->
</script>
</head>
<body bgcolor="white" text="black" link="blue" vlink="purple" alink="red">
<div id="layer1" style="background-color:rgb(204,204,204); width:200px; height:200px; position:absolute; left:16px; top:67px; z-index:1; visibility:hidden;">
<p><a href="#" OnClick="na_hide_layer('layer1');">Fermer</a></p>
<p>blablablablablabla etc</p>
</div>
<p><a href="#" OnClick="na_show_layer('layer1');">voir</a></p>
</body>
</html>
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