Update an iframe/widget dynamically

@russian-dima Took me a couple of years to come up with this solution, so no problem. And in Stuart’s case, he wants to add a query-param to the URL which you can set from code, something like:

https://mydomain.com/myfunction?vid=12345

And in the _use http-function, retrieve the vid-param, do a db-lookup, etc, whatever you want.