Can I use protocol-agnostic URLs in my HTML5 Application Cache Manifest?

Question

We have a number of websites which use the same codebase to run different sites depending on the domain name used, and we're looking to use the HTML5 Application Cache to improve the performance of these sites to cache things like web fonts and other large, rarely-updated files.

Currently, we're hard-coding fully qualified URLs, using HTTPS, just in case one of the websites is using SSL. Our 'static' website server can handle both HTTP and HTTPS, so instead of doing this:

CACHE MANIFEST
# Cache Version 3198.729

https://static.ourdomain.co.uk/fonts/webfont1.eot
https://static.ourdomain.co.uk/fonts/webfont1.ttf
https://static.ourdomain.co.uk/fonts/webfont1.woff

We'd like to be able to do this:

CACHE MANIFEST
# Cache Version 3198.729

//static.ourdomain.co.uk/fonts/webfont1.eot
//static.ourdomain.co.uk/fonts/webfont1.ttf
//static.ourdomain.co.uk/fonts/webfont1.woff

Are we likely to run into any issues by doing this?

Answer 1

//static.ourdomain.co.uk/fonts/webfont1.eot is just a relative URL. It is just as permissible as /fonts/webfont1.eot, wherever relative URLs are acceptable.