We specify a protocol-relative URL in our script path:
// with no http: or https: in front.
This means the script is called using the protocol it inherits from the page:
http or https.
This helps match the script to the page and removes issues like security warnings.
These types of URL are supported in every browser because they're part of the W3C specification, so shouldn't pose a problem.
There are reports of these URLs causing errors to be logged by visits from some of the spiders/bots (for search engines and the like), which aren't coded correctly. These should not affect the site's (or the script's) performance.
Reports of these URLs causing errors, logged by visits from some of the search engine’s web crawlers or bots which aren't coded correctly, should not affect the site's performance or the script's performance.