Chrome canceld Mixed Content 
Analytics:
Mixed Content: The page at ‘https://codecombat.com/’ was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint ‘http://analytics.codecombat.com/analytics’. This request has been blocked; the content must be served over HTTPS.
At Game:
Mixed Content: The page at ‘https://codecombat.com/play/level/gold-rush?team=ogres&opponent=539c88756e1d923105078f04’ was loaded over HTTPS, but requested an insecure resource ‘http://ghbtns.com/github-btn.html?user=codecombat&repo=codecombat&type=watch&count=true’. This request has been blocked; the content must be served over HTTPS.
And:
Mixed Content: The page at ‘https://codecombat.com/play/ladder/gold-rush#my-matches’ was loaded over HTTPS, but requested an insecure resource ‘http://ghbtns.com/github-btn.html?user=codecombat&repo=codecombat&type=watch&count=true’. This request has been blocked; the content must be served over HTTPS.
You can use:
://www.mydomain.de
So the call uses the same protocol as the page.