.
Tu je asi čo potrebuješ vedieť.
<style type="text/css">
#mybox {
display: none;
}
</style>
<script language="javascript">
function showmydiv() {
document.getElementById('mybox').style.display = "block";
}
</script>
</head>
<body>
Text a text.<br>
<input type="button" name="ShowBox" value="Zobraz text" onclick="showmydiv()">
<div id="mybox">
Schovaní text. :-)
</div>
</body>
