Javascript with div tag in Netscape

I am having a problem getting my javascript to work inside a div tag in Netscape 4.0.

I have a layer that appears when a user clicks a link. The layer has 4 thumb nail pictures above a large picture. The user can click on the thumbnails to see a larger version below. In IE, my code works. In Netscape, my code does not work. Thanks for any help. This is very frustrating.

Javascript Code: (see div code below)

<script language="javascript">
<!--
function SwapPic(num)
{
if (num == 1){document.large2.src="../../images/irp/recos/champion/corporate/details1_big.jpg"}
else if (num == 2){document.large2.src="../../images/irp/recos/champion/corporate/details2_big.jpg"}
else if (num == 3){document.large2.src="../../images/irp/recos/champion/corporate/details3_big.jpg"}
else if (num == 4){document.large2.src="../../images/irp/recos/champion/corporate/details4_big.jpg"}
}
//-->
</script>

Div Code:

<div id="div1" style="position:absolute; visibility:hidden; top:439; left:160;">
<table width="400" cellspacing="0" cellpadding="0" border="0">
<tr>
<td><a href="javascript:SwapPic(1)"><img src="../../images/irp/recos/champion/corporate/details5_small.jpg" width="96" height="66" alt="" border="1" /></a></td>
<td><a href="javascript:SwapPic(2)"><img src="../../images/irp/recos/champion/corporate/details6_small.jpg" width="96" height="66" alt="" border="1" /></a></td>
<td><a href="javascript:SwapPic(3)"><img src="../../images/irp/recos/champion/corporate/details7_small.jpg" width="96" height="66" alt="" border="1" /></a></td>
<td><a href="javascript:SwapPic(4)"><img src="../../images/irp/recos/champion/corporate/details8_small.jpg" width="96" height="66" alt="" border="1" /></a></td>
</tr>
</table>
<img src="../../images/irp/recos/champion/corporate/whitefill.gif" width="1" height="5" alt="" border="0" /><br>
<img src="../../images/irp/recos/champion/corporate/details5_big.jpg" name="large2" width="398" height="300" alt="" border="0" /></div>

Gee, this has a familiar ring to it...

If <img name="large2" ...> is inside "div1", you have to reference it as mentioned earlier, as a property of

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;document.div1.document(.large2)

adios

Unfortunately, that is not working. Any insight as to why it isn't working?