textarea required form field

[florida]

How can I make in my form a field that has 5 lines of space entry and make it a required field?

I need a big box like a textarea for input.
This works below but need it to be required. How can I do this??

<tr>
<td align="left" width="311"><b>Info</b></td>
<td width="354">
<textarea name="info" cols="50" rows="6"></textarea>
</td>
</tr>

[Zach Elfers]

<script type="text/JavaScript">
<!--
function required(form) {
if (form.requiredFieldName1.value == "") {
alert("You need to fill out fieldName");
return false;
}
}
//-->
</script>
...
<form onSubmit="required(this);">