jquery ile
<html>

<head>

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.3/jquery.min.js" type="text/javascript"></script>
<script type="text/javascript">

$(document).ready( function () {

$('input#but').click(function () {

$('#acilan').fadeIn('slow')


}
)
}
)

</script>

<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></head>

<body>

<center>

<input type="button" id="but"  value="Sipariş Ver">

<div id="acilan" style="display:none">

 <h1>Bu alana Sipariş Kodlarınızı ekleyiniz </h1>

</div>

</center>

</body>

</html>