check out those resources fara linked to and I found the tutes at www.webmonkey.com useful too....
in essence these are the steps:
a stylesheet:
<style>
#bidnit{
position:absolute;
top:100px;
left:100px;
width:100px;
height:100px;
color:#fff;
background-color:#000;
visibility:visible;
}
</style>
which defines your "layer" although that's not such a useful term in this context cos it can mean different things - think more in terms of page elements....
the element on the page:
<body>
<span id="bidnit">Whooah bidnit!</span>
... rest of your page...
</body>
and some javascript to manipulate it:
//in the page header
<script language="JavaScript">
function swapVis() {
if (document.all["bidnit"].style.visibility=='hidden') {
document.all["bidnit"].style.visibility = 'visible';
} else {
document.all["bidnit"].style.visibility = 'hidden';
}
}
</script>
then you can call that function to turn the visibility on and off, with a link in the webpage like:
<a href="javascript:swapVis();">swap visibility</a>
or even from a flash movie, using getURL:
getURL("javascript:void(0);swapVis();");
as I said, the way you refer to page elements differs in IE & NN, so you will need to look into this if you want to make something rock solid, more recent browsers will all be OK though.....hope that helps,