Заставить работать под оперу

<script LANGUAGE="JavaScript">
<!-- Begin
browserName = navigator.appName;
browserVer = parseInt(navigator.appVersion);

ns3up = (browserName == "Netscape" && browserVer >= 3);
ie4up = (browserName.indexOf("Microsoft") >= 0 && browserVer >= 4);

function doPic(imgName) {
if (ns3up || ie4up) {
imgOn = ("" + imgName);
document.mainpic.src = imgOn;
}
}
// End -->
</script>

<img name="mainpic" src="images/1.jpg" width=240 height=180 border=0>
<a href="javascript:doPic('images/2.jpg');"><img id="Image0" src="images/1.jpg" border="0" width="80" height="60"></a>

function doPic(imgName) {
imgOn = ("" + imgName);
document.mainpic.src = imgOn;
}