JavaScript

<script language="JavaScript">
function setVisibility(id) {
if(document.getElementById('bt1').value=='Hide Layer'){
document.getElementById('bt1').value = 'Show Layer';
document.getElementById(id).style.display = 'none';
}else{
document.getElementById('bt1').value = 'Hide Layer';
document.getElementById(id).style.display = 'inline';
}
}
</script>

HTML

<input type=button name=type id='bt1' value='Show Layer' onclick="setVisibility('sub3');";> 
<div id="sub3">Message Box</div>

Style

<style type="text/css">
#sub3 {
position: absolute;
left: 250px;
top: 100px;
background-color: #f1f1f1;
width: 280px;
padding: 10px;
color: black;
border: #0000cc 2px dashed;
display: none;
}
</style>