What is the difference between RegExp’s exec() function and String’s match() function?

exec with a global regular expression is meant to be used in a loop, as it will still retrieve all matched subexpressions. So:

var re = /[^\/]+/g;
var match;

while (match = re.exec('/a/b/c/d')) {
    // match is now the next match, in array form.
}

// No more matches.

String.match does this for you and discards the captured groups.

One picture is better, you know...

re_once = /([a-z])([A-Z])/
re_glob = /([a-z])([A-Z])/g

st = "aAbBcC"

console.log("match once="+ st.match(re_once)+ "  match glob="+ st.match(re_glob))
console.log("exec once="+ re_once.exec(st) + "   exec glob="+ re_glob.exec(st))
console.log("exec once="+ re_once.exec(st) + "   exec glob="+ re_glob.exec(st))
console.log("exec once="+ re_once.exec(st) + "   exec glob="+ re_glob.exec(st))

See the difference?

Note: To highlight, notice that captured groups(eg: a, A) are returned after the matched pattern (eg: aA), it's not just the matched pattern.

/regex/.exec() returns only the first match found, while "string".match() returns all of them if you use the g flag in the regex.

See here: exec, match.