Let the browser choose the protocol

Use protocol independent URLs whenever possible so that the browser will choose the protocol related to the protocol which the page is delivered with.

Example issues

• When your page is delivered via https and you provide a youtube video only via http the most browsers (e.g. Firefox, Chrome) won't display the video.
• When you deliver your youtube video via https://youtu.be/jyElDp98HdI your test which checks that the embeded video is rendered in the view will fail because your test server doesn't use https

Solution

Let your links look like //youtu.be/jyElDp98HdI and you will be fine, server side and test side.