Changing the CSS Href in NS 6/7?

If I have a relative style sheet:
<link rel="stylesheet" href="CSS/styleSheet1.css" type="text/css">

Is there anyway, through *client side code*, to change the entire
 reference to another CSS?

I gave the link element an id and accessed it via getElementById to
 change it's HREF, but the result was problematic (buggy?). It would
 work repeatedly, except sometimes it would hang or leave certain CSS
 properties unchanged bewteen style sheets.