function gymCallback(results2, status2) {
        var totalRating = 0,
            ratedCount = 0;

        results2.forEach(function( place ) {
            if (place.rating !== undefined) {
                ratedCount++;
                totalRating += place.rating;
            }
        });


        var averageRating = results2.length == 0 ? 0 : totalRating / ratedCount;
        var averageRatingRounded = averageRating.toFixed(1);


        var averageGymRatingTB = document.getElementById('gymAvgRating');
        averageGymRatingTB.value = averageRatingRounded;
    }

<p>
Gyms: &nbsp; &nbsp; &nbsp; &nbsp;
<input type="text" size="10" name="gymAvgRating" id="gymAvgRating" />
</p>

<li data-toggle="collapse" data-target="#fitness" class="collapsed">
                <a onclick="clearMarkers();GymReport();" href="#"><i class="fa fa-heart fa-lg"></i> Fitness <span
                    class="arrow"></span></a>
            </li>