I've got google map to work on my website and now I have come across a problem.

For google map to work I need to have onload="load(); " onunload="GUnload()" in the body.

But when I do this it causes errors throughout the rest of the site as its only being used on the location page.

How do I make it so onload="load(); " onunload="GUnload()" only gets called on on location.ascx

The obvious answer is;

only put the code on that page.

However I take it that is NOT what you are actually asking.

As the page is .ascx that would be in ASP.NET, so I'd guess that you need some code to only include the code IF the page name is location.ascx

We need more info on your site to be able to provide code, such as what language the site is coded in.
There is a .net forum here and this thread is flagged to be moved there.

in ASP VbScript it would be

<%
if instr(request.servervariables("SCRIPT_NAME"),"location.ascx") = 0 then 
%>
     <!--#include virtual="page_with_GoogleMap_code.ext" -->
<%
end if
%>