更改功能时JSXgraph不移动点

如何解决更改功能时JSXgraph不移动点

我正在使用JSXgraph向学生展示limsups和liminfs。该版本在这里有效-http://ibldynamics.com/exercises/ex2_56.html

这是代码：

<div style="width: 500px; height: 40px;">
        <p style="display: inline;">N:</p>
       // Create a slider for the values of N
        <input id="NSlider" type="range" min="1" max="19" value="1" step="1" style="width: 50%;">
        <p style="display: inline;"><span id="NOut"></span></p>
        <script>
            // Get the value of N from the slider
            var NSlider = document.getElementById("NSlider");
            var NOutput = document.getElementById("NOut");
            NOutput.innerHTML = NSlider.value; // Output value for student to see
        </script>
    </div>
    <!-- Create board with points -->
    <div id="Box" class="jxgBox" style="width:500px; height:500px;">
        <script type="text/javascript">
            // Create board
            var board = JXG.JSXGraph.initBoard('Box',{
                boundingBox: [-1,2,21,-0.2],axis: true,grid: true
            });
            // Generate points in the sequence and graph points of the sequence
            var i;
            var s = [null];
            for (i = 1; i <= 20; i++) {
                s.push(1 + Math.pow(-1,i) / i);
                board.create('point',[i,s[i]],{
                    color: 'yellow',fixed: true,withLabel: false
                });
            }
            // Genereate liminfs and limsups
            var infs = [null],sups = [null];
            for (i = 1; i <= 20; i++) {
                infs.push(Math.min.apply(null,s.slice(i + 1)));
                sups.push(Math.max.apply(null,s.slice(i + 1)));
            }
            // Graph liminf and limsup points
            var liminf = board.create('point',[
            function() { return NSlider.value; },function() { return infs[NSlider.value]; }],{
                color: 'blue',withLabel: false
            });
            var limsup = board.create('point',function() { return sups[NSlider.value]; }],{
                color: 'orange',withLabel: false
            });
     
            board.update()
        </script>
    </div>
        <script>
            // Set board to update when the N slider is updated
            NSlider.oninput = function () {
            NOutput.innerHTML = this.value; // Output value for student to see
                liminf.moveto([NSlider.value,infs[NSlider.value]]);
                limsup.moveto([NSlider.value,sups[NSlider.value]]);
            }
        </script>

问题是我在这里使用的版本-http://ibldynamics.com/exercises/ex2_57.html

我只改变了两件事。我用来生成点的函数是s.push((-1)**i*(1 + (1 / i)));，边界框要大一点。由于某些原因，蓝点将不再显示。

有什么想法吗？