Odd or Even

<script type="text/javascript">

<!--
function IsWhat(num) {
num = num/2;
num = num.toString();
if (num.indexOf(".") > -1 ) {
document.getElementById("txt").innerHTML="This number is ODD"
}
 else {
document.getElementById("txt").innerHTML="This number is EVEN"
}
}
//-->
</script>

<form name="f1">
<input type="text" name="t1" value="2" size="6">
<input type="button" value="Number Test" onclick="IsWhat(t1.value)">
</form>

<div id="txt">Odd or Even</div>