<br>

 1) OPEN DEVELOPER CONSOLE. ensure the mobile-phone symbol is clicked ,so you are viewing in mobile format<br>

 2) Click the console window in developer console. 

 3) click timepicker<br>

 4) Do not select anything, simply click "ok" - then you see the JS error (x6 times)<br>

​

<div class="mb-10 col-xs-12 col-sm-3 col-md-3 col-lg-3 col-xl-3" >

                            <div class="form-outline timepicker text-align-right" data-mdb-format24="true" data-mdb-increment="true">

                                <input type="text" class="form-control" data-mdb-toggle="timepicker" id="von" name="Von" required />

                                <label class="form-label" for="von" style="margin-top: 2px;">timepicker</label>

                            </div>

                    </div>