Why does “//” instead of http or https before the actual link work?

Question

I just noticed that I can write //google.com instead of http://google.com and it still works.

Is that some kind of short-hand? Maybe it's something that's built in my browser (Chrome 14)?

Is it safe to use double-slash instead of http and https?

Answer 1

How something like // is handled by the browser will vary by browser. As the standard usage case is http:// and would work across all browsers without a problem.

That being said, the majority of browsers will attempt HTTP where possible since that is what the browsers are used most often for. It is also the safest choice, HTTP traffic is sandboxed as best as possible by the browser and should be more secure than assuming the address is local.