I've been trying for the last our to create a button on Zoho CRM. I succeeded in doing this but I cannot for the life of me get this working with an iframe.

openUrl("http://www.google.com","new window");

This works, but in my custom function, this using "iframe" does not. 

What is the exact function I have to use so when the button is clicked, an iframe pops up within the crm?

openUrl("http://google.com","iframe","googleiframe")

Can anyone please help?