First the snippet (watch for line wrapping when copy/pasting this):

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1// current link highlighting
2 $('#topLinksNav a[href="<cfoutput>#listLast(cgi.script_name,'/')#</cfoutput>"]').first().addClass('currentLink').parents('li').addClass('currentLink');
3// make sure top level link for this element is also highlighted
4 $('#topLinksNav ul').has('.currentLink').siblings('a').addClass('currentLink');

This finds any link with an 'href' attribute matching the name of your current page, e.g. "pagename.cfm" , and adds a class of 'currentLink' (note this is in a site where all pages are in the root directory - obviously this needs to be changed to match your site structure, but the same idea applies).

A sample of the ul/li menu structure I'm using is below.

Then you just need a CSS rule for the '.currentLink' class, perhaps

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1#topLinksNav li.currentLink{
2 set some background color here
3}
4
5or
6
7#topLinksNav >
li > a.currentLink{
8 set a highlighted text color here only for top level links
9}

Here's the sample menu structure for the syntax above something like

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1<ul id="topLinksNav">
2<li>
3<a href="index.cfm">Top Level Page</a>
4 <ul>
5 <li>
6 <a href="subpage1.cfm">Secondary Menu Page</a>
7 </li>
8 <li>
9 <a href="subpage2.cfm">Secondary Menu Page</a>
10 </li>
11 </ul>
12 </li>
13<li>
14<a href="contact.cfm">Top Level Page</a>
15 <ul>
16 <li>
17 <a href="subpage1.cfm">Secondary Menu Page</a>
18 </li>
19 <li>
20 <a href="subpage2.cfm">Secondary Menu Page</a>
21 </li>
22 </ul>
23 </li>
24</ul>