SSL and mixed content due to CSS background images

Question

I have a web page containing am entry form. HTTPS is enabled via an Apache redirect for all requests matching that page. Unfortunately, because the CSS pulls in external images using 'background-image: url(/images/...)', the browser will generate a warning message that the page contains mixed content.

What's the best way to resolve this issue?

Answer 1

You should also enable HTTPS for your static resources, and then make sure that the <link> refers explicitly to the HTTPS url for the CSS resource (whose relative urls will then be interpreted relative to the HTTPS base of the CSS file).