在VisNetwork中选择节点时，如何显示节点的标签？

var nodes = [
  { id: 1, label: "Node 1", shape: "image", image: "image_url" },
  { id: 2, label: "Node 2", shape: "circle" }
];

var edges = [
  { from: 1, to: 2 }
];

var container = document.getElementById("network");

var data = {
  nodes: nodes,
  edges: edges
};

var options = {};

var network = new vis.Network(container, data, options);