<form id="form" action="">
	<fieldset>
	<legend>Nmero por extenso</legend>
	Currency ? <input type="checkbox" name="cur" id="cur" value="" /><br />
	Nmero <input type="text" name="num" /><br /><br />
	<input type="submit" value="String.extenso()" />
	</fieldset>
</form>

<script type="text/javascript">
//<![CDATA[

var f = document.forms.form;
addEvent(f, "submit", function(e){
	e.preventDefault();
	alert(f.num.value.extenso(f.cur.checked));
});

//]]>
</script>