How do I delete a cookie that I have set with Javascript

[dreaming of nascar]

I am experimenting with cookies in Javascript and am able to set and read them, but after I do another set, I read it and the old information is in front of what I have just set. How do I delete a cookie that I have set and is it possible to overwrite the contents of a cookie's old values with the new values? Any information would be apprecated!
I hope that this makes sense. Thanks.

[tedster]

I don't do much with javascript cookies, but I believe you can set a new cookie with the same path and name -- but use an expires date that's already past. So your new cookie overwrites the original cookie, but then the browser will zap it because it's expired.