Jointjs在拖动链接目标时，让它调用自定义函数

var graph = new joint.dia.Graph();

var paper = new joint.dia.Paper({
  el: document.getElementById('paper'),
  model: graph,
  width: 800,
  height: 600,
});

function customFunction() {
  alert('Custom function called!');
}

var rect = new joint.shapes.standard.Rectangle();
rect.position(100, 100);
rect.resize(100, 40);
rect.attr({
  body: {
    fill: 'blue',
  },
  label: {
    text: 'Drag me',
    fill: 'white',
  },
});
rect.addTo(graph);

rect.on('change:position', function(element) {
  customFunction();
});