findURLs.js

var findURLs = (function() {
    var bracketBalance = function(text) {
        var brackets = {
                "(": 1,
                ")": -1,
                "[": 100,
                "]": -100,
                "{": 10000,
                "}": -10000
            },
            i, c, b = 0;
        for (i = 0; i < text.length; i++) {
            c = text.charAt(i);
            if (c in brackets) b += brackets[c];
        }
        return b;
    };

    return function(text) {
        var urlRe = /\b(((https?|ftp):\/\/|www\.)[^\s<>]+|([a-zа-я0-9][a-zа-я0-9-]*\.)+(ru|com|net|org|рф|xn--[a-z0-9]+)(?![a-zа-я0-9-])[^\s<>]*)/ig;
        var finalPuncts = /[\x21-\x2e\x3a-\x3f\x5b-\x60\x7b-\x7e\u2026]+$/; // Base latin punctuation except '/' include ellipsis

        var found, founds = [];
        while ((found = urlRe.exec(text)) !== null) {
            founds.push({
                match: found[0],
                pos: found.index,
                withProtocol: !!found[2]
            });
        }

        return founds
            .map(function(f) {
                // tail punctuation trim & bracket match

                var m = finalPuncts.exec(f.match);
                if (m === null) return f;
                var fin = m[0];

                if (!/[)}\]]/.test(fin)) {
                    // no closes brackets, just cut it all
                    f.match = f.match.substr(0, f.match.length - fin.length);
                    return f;
                }

                var b = bracketBalance(f.match.substr(0, f.match.length - fin.length));
                if (b === 0) {
                    // brackets balanced, just cut it all
                    f.match = f.match.substr(0, f.match.length - fin.length);
                    return f;
                }

                m = /[^)}\]]+$/.exec(fin);
                if (m !== null) {
                    // trim non-brackets
                    fin = fin.substr(0, fin.length - m[0].length);
                    f.match = f.match.substr(0, f.match.length - m[0].length);
                }

                for (var i = 0; i < fin.length; i++) {
                    b += bracketBalance(fin.charAt(i));
                    if (b === 0) {
                        f.match = f.match.substr(0, f.match.length - fin.length + i + 1);
                        return f;
                    }
                }
                return f;
            })
            .filter(function(f) {
                urlRe.lastIndex = 0;
                return urlRe.test(f.match);
            })
            .map(function(f) {
                // url-s

                f.url = f.withProtocol ? f.match : "http://" + f.match;
                delete f.withProtocol;
                return f;
            });

        return founds;
    };
})();