if it's an entire form you are better off hiding it on page load and showing it when the button is pressed:
Code:
<!doctype html>
<html>
<head>
<style>
#myform{
display:none;
}
</style>
</head>
<body>
<input type="button" value="show form" onclick="showIt()"/>
<form id="myform">
<input/><br>
<input/>
</form>
<script>
function showIt(){
document.getElementById("myform").style.display="block";
}
</script>
</body>
</html>