2 unexplained Javascripts appearing on remote pages

Can anyone tell me how/why these Javascripts are appearing in my source code, and what their function is please? I haven't scripted them and they are not on my actual html document, but they are there when you click "View source" online. Is this auto-generated code by Dreamweaver, or my webhost, or has someone hacked into my webhost? Do I need to be worried? How do I remove them if necessary?

Thank you!

The first one appears in the head section:


<script language="JavaScript">
<!--

function SymError()
{
return true;
}

window.onerror = SymError;

var SymRealWinOpen = window.open;

function SymWinOpen(url, name, attributes)
{
return (new Object());
}

window.open = SymWinOpen;

//-->
</script>


and this second one appears after the html closing tag:
<script language="JavaScript">
<!--
var SymRealOnLoad;
var SymRealOnUnload;

function SymOnUnload()
{
window.open = SymWinOpen;
if(SymRealOnUnload != null)
SymRealOnUnload();
}

function SymOnLoad()
{
if(SymRealOnLoad != null)
SymRealOnLoad();
window.open = SymRealWinOpen;
SymRealOnUnload = window.onunload;
window.onunload = SymOnUnload;
}

SymRealOnLoad = window.onload;
window.onload = SymOnLoad;

//-->
</script>

That's Norton's auto-code insertion.

http://www.webdevtips.com/webdevtips/js/nis.shtml

Thank you very much for the info and the link - fascinating reading, but I do have to agree with the author of the article!

I certainly didn't know code could be added locally to my webpages!

Thanks again!

It's fairly common for end-users to have extra code inserted into pages they are viewing. Any number of cookie/popup blocking programs do it, Firefox's Greasemonkey extention alllows inserting arbitrary javascript code into pages, and my favorite, The Proxomitron, allow arbitrary javascript/html insertion and on the fly rewriting of pages.

Make your pages robust enough to survive the little assaults, and user-friendly enough to discourage the major assaults.

I don't use pop-ups or any sort of ads on any of my sites, so hopefully the "end user" shouldn't have any problems.