podria ser asi
Código HTML:
<html>
<head>
<script type="text/javascript">
function ocultarform()
{
document.getElementById("formulario").style.visibility="hidden";
}
</script>
</head>
<body>
<form id="formulario">
<input type="text" name="textfield">
<input name="Enviar" type="submit" onclick="ocultarform()" value="Enviar" />
</form>
</body>
</html>