Question

Javascript has an overload for string.replace(...) that takes a Regular Expression and a callback function, but I’m having a very difficult time finding ANY documentation on this specific overload!

W3Schools.com doesn’t mention this overload. I’ve also gone through dozens of Google results, but every page talks about string.replace(string, string) or string.replace(RegExp, string). It’s almost embarrassing not being able to find a solid Javascript documentation reference! My Google-fu has let me down.

I am mostly interested in knowing everything about the callback function, such as input parameters and return values. I’m also interested in any possible cross-browser issues.

Answer 1

MDN, of course:
https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/String/replace

Btw, it’s specified in the ECMAScript specification, duh.

If replaceValue is a function, then for each matched substring, call
the function with the following m + 3 arguments. Argument 1 is the
substring that matched. If searchValue is a regular expression, the
next m arguments are all of the captures in the MatchResult (see
15.10.2.1). Argument m + 2 is the offset within string where the match occurred, and argument m + 3 is string. The result is a String value
derived from the original input by replacing each matched substring
with the corresponding return value of the function call, converted to
a String if need be.