How to pass dynamic parameters in an iframe inside Webtab

How to pass dynamic parameters in an iframe inside Webtab

Hello,

I have a custom url like htts://www.test.com?zoho_id= 123456789.

I know that if a have a custom button and using a custom function (openurl) I can open the above link by passing dynamically the Zoho ID (lets say the record ID in the Contacts Module).

I would like to open this url as an iframe inside Zoho CRM somehow. Is there any way to do that?
I know that there are Web Tabs. But how can I pass dynamic values in the iframe from the openurl deluge function?
Webtab also has an option with the name Append Parameters but I can only chose parameters from Users and Organisation parameters.

Any idea of how to achive it?