iframe width and height in percentage or responsive?

iframe width and height in percentage or responsive?

Sorry for re-posting my problem.
I'll try to explain better my needs here.

I "simply" need to open a popup containing an iframe using percentages.
So that a popup will fill the viewport by, say, 90%width and 90%height.
But I've found only samples with fixed width. How the hell can a fixed width popup fit on smaller screens?

For instance, once I click the button that will trigger the popup, the popup will be sized to 90% width of the viewport and 90% heigth of the viewport.

Is there a sample that explains how to do this with Jquery mobile 1.3.0?
Or, at least something that allow me to make a popup responsive, that will almost fill any viewport?

TIA

tony