How to embed HTTP content inside a HTTPS webpage / Mixed content problems

If you are running a webpage and you decide to move to SSL protection you can encounter the following problem: Inside your webpage you are using tags like "iframe", "script" or "link" pointing to HTTP servers. This is considered as mixed active content (mozilla):

Mixed active content is content that has access to all or parts of the Document Object Model of the HTTPS page. This type of mixed content can alter the behavior of the HTTPS page and potentially steal sensitive data from the user. Hence, in addition to the risks described for mixed display content above, mixed active content is vulnerable to a few other attack vectors.

And this will not work...

The best solution is: change all links from HTTP to HTTPS and you are done.

But there are still websites which offer their content in HTTP only. If you really trust them, you can do the following:
Add the link inside a https proxy like https://ssl-proxy.my-addr.org/myaddrproxy.php/http/yourlink

Of course this is not an excellent solution, but a workaround which allows you to protect your website and if you seperate this solution from the pages, which deal with sensitive content you should be fine...