Zoho Crm account  login/password and Ruby On Rails application that  has 2 fields for entering this login/password.

What I need:

To get API key programmatically (means using jquery, javascript, etc.).

Steps that I'm doing:

a) assume my app's user has filled these 2 fields  
b) next action that I should do (and ASKING IN THIS TOPIC):

 using javascript or something else I should be able (in background invisibly for the user(may be in iframe) to log into zoho crm account and somehow navigate to the settings page with API key and pass this API key back to the main window with 2 fields (login/password).

How can I do that ?