I know an https link in a regular http page can cause trouble, but can the opposite cause trouble as well? I'm thinking about always replacing the http address of trailer urls in my database with https when a user inputs the url. I'm just not sure if there can be bad consequences, especially if I force https but that the target link is not SSL (Would it be better to keep http in that situation, or changing to https would not change anything?).
This question is probably a duplicate but there are a million questions about the opposite of what I'm asking, so I cannot find on SO. If it's a duplicate, please help me with the link to original question :)
HTTPS hyperlinks (used in anchors) in a page delivered over HTTP do not cause any trouble. Similarly, HTTP hyperlinks (used in anchors) in a page delivered over HTTPS also do not cause any trouble.
The only issue is if resources such as images, scripts, styles and FORM post URLs use HTTP references in a page delivered over HTTPS (mixed content).