Hi Aniz,
Here is a simple example of how u can hide/show layers in NS,

This wrote the code in a hurry , so it might contain errors, i will post a better version of the code when i get home from work in few hours.

Hope this helps

Code:
<html>
<head>
<script>
function testit()
{
var vis;
vis=document.layers["test"].visibility;


if (vis=="hide")
	{
	document.layers["test"].visibility="visible";
	document.form1.btn1.value="Hide";
	}
else
	{
	document.layers["test"].visibility="hidden";
	document.form1.btn1.value="Show";
	}
}
</script>
</head>
<body>
<layer name="test" >
<h1>Test</h1>
</layer>
<br><br><br>
<form name=form1>
<input type =button value="Hide" onclick="javascript:testit()" name=btn1>

</form>
</body>
</html>