<form action="">
<fieldset>
	<legend>Mnimo Mltiplo Comum</legend>
	<label for="numbers">Nmeros:</label> <input type="text" id="numbers" value="2 3 4 7 8" />
	<br /><input type="submit" value="Calcular MMC" />
</fieldset>
</form>

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

//http://www.jsfromhell.com/geral/event-listener
addEvent(document.forms[0], "submit", function(e){
	alert(mmc(document.forms[0].numbers.value.split(" ")))
	e.preventDefault();
});

//]]>
</script>