I am loading a responsive website inside a dynamic iframe on Mobile Safari, I set the width of the iframe via JS to the viewport width and you can see the responsive layout for a second, then the iframe "explodes" to the right and down and the desktop version is loaded. I tried this with a couple of websites and the results is the same.
Why is it loading the desktop version and how can I force the iframe to load the mobile version instead?
Update:
It seems it might be due to the library I am using for the popup in which I am loading the iframe (Magnific popups), I added an iframe to the body of the page and it doesn't have that problem.
Added scrollable: no to the iframe fixed it. Usual voodoo of HTML/CSS.