Below code works on localhost, but not on live server.
MAIN EDIT:
Only 1 thing remains which is not working:
On AJAX success this will being executed:
$(".FixedDiv").addClass("panel-danger");
setTimeout(close, 500);
$("#label_" + res[2]).html(data.score_result);
$("#monitoring_score").html(data.calculated_score);
How ever, the label(for example) is not being updated. The label needs to be updated by the score which is given (data.score_result).  
Ajax code:
$('.rating').on('rating.change', function () {
  var rating_id = $(this).attr('id');
  var res = rating_id.split("_");
  var comment = $("#comments_" + res[2]).val();
  var score = $("#item_score_" + res[2]).val();
  var post = 'controller=QualityMonitoring&task=setScore&monitor_id='
    + <?php echo $query['monitor_id']; ?>
    + '&q=' + res[2] + '&item_score=' + score + '&comment=' + comment;
  $.ajax({
    url: "controller.php",
    type: "POST",
    data: post,
    cache: false,
    dataType: "json",
    beforeSend: function () {
      saveScore();
    },
    success: function (data) {
      $(".FixedDiv").addClass("panel-danger");
      setTimeout(close, 500);
      $("#label_" + res[2]).html(data.score_result);
      $("#monitoring_score").html(data.calculated_score);
    }
  });
});
When I put alert('test'); above the $.ajax({ code it shows 'test'. When I put the alert INSIDE (just below) the $.ajax({ code, it does not show the alert. 
saveScore function:
function saveScore() {
  var docHeight = $(document).height();
  $("body").append("<div id='overlay'></div>");
  $("#overlay")
    .height(docHeight)
    .css({
      'opacity': 0.4,
      'position': 'absolute',
      'top': 0,
      'left': 0,
      'background-color': 'black',
      'width': '100%',
      'z-index': 5000
    });
}
Results/info:
- alert(post);gives me the correct data result.
- saveScoreis executed, but won't close afterwards (- setTimeout).
- #labeland- #monitoring_scoreare not being updated like it has to do.
- using jquery-3.1.1.
I'm distraught on how to solve this. Anyone has an idea on how to fix?
Extra:
@Teemu:
Add an error handler to the AJAX call too, most likely it's the server-side which passes an error instead of data. Or open Network tab from the DevTools, and see if you're actually getting 200 OK message and the data.
Edit 1: (Whole javascript code):
<script>
    $(document).ready(function () {
        $(".nav-tabs a").click(function () {
            $(this).tab('show');
        });
    });
    $(document).ready(function () {
        $('.summernote').summernote({
            height: 450,   //set editable area's height
            toolbar: [
                ['view', ['fullscreen']],
                ['help', ['help']]
            ],
            codemirror: { // codemirror options
                theme: 'monokai'
            }
        });
    });
    jQuery(document).ready(function () {
        $('.nvt').on('click', function () {
            // get the id:
            var id = $(this).attr('id');
            var res = id.split("_");
            // Reset rating:
            var rating_input = "item_score_" + res[1];
            $('#' + rating_input).rating('update', 0);
            var comment = $("#comments_" + res[1]).val();
            var score = 0;
            var post = 'controller=QualityMonitoring&task=setScore&monitor_id=' + <?php echo $query['monitor_id']; ?> +'&q=' + res[1] + '&item_score=' + score + '&comment=' + comment;
            $.ajax({
                url: "controller.php",
                type: "POST",
                data: post,
                cache: false,
                dataType: "json",
                beforeSend: function () {
                    saveScore();
                },
                success: function (data) {
                    $(".FixedDiv").addClass("panel-danger");
                    setTimeout(closediv, 500);
                    $("#label_" + res[1]).html(data.score_result);
                    $("#monitoring_score").html(data.calculated_score);
                },
                error: function (data) {
                    $(".FixedDiv").addClass("panel-danger");
                    setTimeout(closediv, 500);
                    $("#label_" + res[1]).html(data.score_result);
                    $("#monitoring_score").html(data.calculated_score);
                }
            });
        });
        $('.rating').on('rating.change', function () {
            var rating_id = $(this).attr('id');
            var res = rating_id.split("_");
            var comment = $("#comments_" + res[2]).val();
            var score = $("#item_score_" + res[2]).val();
            var post = 'controller=QualityMonitoring&task=setScore&monitor_id=' + <?php echo $query['monitor_id']; ?> +'&q=' + res[2] + '&item_score=' + score + '&comment=' + comment;
            $.ajax({
                url: "controller.php",
                type: "POST",
                data: post,
                cache: false,
                dataType: 'json',
                beforeSend: function (data) {
                    saveScore();
                },
                success: function (data) {
                    $(".FixedDiv").addClass("panel-danger");
                    setTimeout(closediv, 500);
                    $("#label_" + res[2]).html(data.score_result);
                    $("#monitoring_score").html(data.calculated_score);
                },
                error: function(data) {
                    console.log("ERROR: ", data);
                }
            });
        });
        $('.savecomment').on('blur', function () {
            var comment_id = $(this).attr('id');
            var res = comment_id.split("_");
            var commentraw = $("#comments_" + res[1]).val();
            var comment = encodeURIComponent(commentraw);
            var post = 'controller=QualityMonitoring&task=setComment&monitor_id=' + <?php echo $query['monitor_id']; ?> +'&q=' + res[1] + '&comment=' + comment;
            $.ajax({
                url: "controller.php",
                type: "POST",
                data: post,
                cache: false,
                dataType: "json",
                success: function (data) {
                    if (data.result == 666) {
                        $("#comments_" + res[1]).css("background-color", "#ffcccc");
                    }
                }
            });
        });
    });
    $(document).on('change', '.btn-file :file', function () {
        var input = $(this),
                numFiles = input.get(0).files ? input.get(0).files.length : 1,
                label = input.val().replace(/\\/g, '/').replace(/.*\//, '');
        input.trigger('fileselect', [numFiles, label]);
    });
    $(document).ready(function () {
        $('.btn-file :file').on('fileselect', function (event, numFiles, label) {
            var input = $(this).parents('.input-group').find(':text'),
                    log = numFiles > 1 ? numFiles + ' files selected' : label;
            if (input.length) {
                input.val(log);
            } else {
                if (log) alert(log);
            }
        });
    });
    function closediv() {
        $(document).unbind("keyup");
        $("#overlay").fadeOut("slow", function () {
            $("#overlay").remove();
            $(".FixedDiv").removeClass("panel-danger");
        });
    }
    function saveScore() {
        var docHeight = $(document).height();
        $("body").append("<div id='overlay'></div>");
        $("#overlay")
                .height(docHeight)
                .css({
                    'opacity': 0.4,
                    'position': 'absolute',
                    'top': 0,
                    'left': 0,
                    'background-color': 'black',
                    'width': '100%',
                    'z-index': 5000
                });
    }
    $(document).ready(function () {
        var $sidebar = $(".FixedDiv"),
                $window = $(window),
                offset = $sidebar.offset(),
                topPadding = 55;
        $window.scroll(function () {
            if ($window.scrollTop() > offset.top) {
                $sidebar.stop().animate({
                    marginTop: $window.scrollTop() - offset.top + topPadding
                });
            } else {
                $sidebar.stop().animate({
                    marginTop: 24
                });
            }
        });
    });
</script>
 
     
     
     
     
     
    