How to test if a URL string is absolute or relative?

Question

How can I test a URL if it is a relative or absolute path in Javascript or jQuery? I want to handle accordingly depending if the passed in URL is a local or external path.

Answer 1

It should not start with a slash or hash, and it should not contain a double slash if not preceded by question mark or hash? I would not test that with a single regexp, it would be very complicated to match "no double slash".

function test(s) {
    return s.charAt(0) != "#"
      && s.charAt(0) != "/"
      && ( s.indexOf("//") == -1 
        || s.indexOf("//") > s.indexOf("#")
        || s.indexOf("//") > s.indexOf("?")
    );
}

would be easier, clearer and imho faster.