Command That Will Read The Url That Was Called...?

If I have a link to a URL such as <a
href="http://www.mysite.com/somecode.htm?5">Link1</a>, and if I include
javascript in the somecode.htm file, is there a javascript command that I
can use which will read the argument 5?

For that matter, is there anyway to send an argument to the javascript code
of an html link you are calling. Server scripts are not an option for me.

For example, assuming that index.htm contains 50 links, I would like each
link to point to the same html file, but I want that javascript code in that
html file to execute something different depending on which link was
clicked.

My only other alternative would be to create 50 similar html files which to
me looks like amateur or bad coding.