JavaScript

<script language="JavaScript">
function setVisibility(id1,id2) {
if(document.getElementById('bt1').value=='Hide Layer'){
document.getElementById('bt1').value = 'Show Layer';
document.getElementById(id1).style.display = 'none';
document.getElementById(id2).style.display = 'none';
}else{
document.getElementById('bt1').value = 'Hide Layer';
document.getElementById(id1).style.display = 'inline';
document.getElementById(id2).style.display = 'inline';
}
}
</script>

HTML

<input type=button name=type id='bt1' value='Show Layer' onclick="setVisibility('sub3','sub4');";> 
<div id="sub3">Message Box 3</div>
<br><br><br>
<div id="sub4">Message Box 4</div>

Style

<style type="text/css">
#sub3,#sub4 {
position: relative;
left: 250px;
top: 50px;
background-color: #f1f1f1;
width: 280px;
padding: 10px;
color: black;
border: #0000cc 2px dashed;
display: none;
}
</style>