Q: How to force iframe to use https already embed on other https websites? I had website without https i.e. SSL. Other websites embed the page of my website using iframe.
<iframe src="http://mywebsite.com/app" ... />

That worked fine until their website was http only. Now their website is https and does not load iframe because it is only http. Now i have added SSL.  without contacting the other website how to make iframe work on their website?
Please help.

A: 
... without contacting the other website

Impossible. The browser will not even try to contact your site since it is a HTTP resource included inside HTTPS. The URL has to be changed in embedding site and this can only be done by the maintainer of the embedding site.
