String.Substitute.js

String.implement({

    substitute: function(object, regexp){
        return this.replace(regexp || (/\\?\{([^{}:]+)(?::([^{}:]+))?\}/g), function(match, name, format){
            if (match.charAt(0) == '\\') return match.slice(1);
            var value = (object[name] != null) ? object[name] : '';
            if (format && typeof value.format == 'function') value = value.format(format);
            return value;
        });
    }

});