Have customers login from a different webpage

How would I go about having customers login in the their account by signing in on a different webpage?

I have a main site and a separate zencart shopping site. How would I have a customer sign into the Zencart shipping site from my main site?

I've searched the forum and couldn't find any posts on this topic.

Please any help would be much appreciated. Thanks

Mike

The reason you're not finding much is that what you are proposing is like going to your next door neighbor's house to get something out of your refrigerator.

Zen Cart uses it's session keys to perform many tasks, including keeping track of items in the cart.

Zen Cart s a powerful engine but you have to put it in the "car" you are using. It's flexible enough that you can make it look any way you want. But, trying to create a session id from another source would be like changing the spark plugs of the engine by going through the trunk.