例如，我如何在codemirror中创建上下文相关菜单？

<link rel="stylesheet" href="codemirror.css">
<script src="codemirror.js"></script>

var editor = CodeMirror(document.body, {
  value: "function myScript(){return 100;}\n",
  mode:  "javascript"
});

<div id="context-menu" style="display:none; position:absolute; background:white; border:1px solid black;">
  <ul>
    <li><a href="#" onclick="formatCode()">格式化代码</a></li>
    <li><a href="#" onclick="commentCode()">注释代码</a></li>
  </ul>
</div>

editor.on("contextmenu", function(cm, event) {
  event.preventDefault(); // 阻止默认的上下文菜单显示
  var menu = document.getElementById("context-menu");
  menu.style.display = "block";
  menu.style.left = event.pageX + "px";
  menu.style.top = event.pageY + "px";
});

function formatCode() {
  // 实现代码格式化逻辑
  console.log("格式化代码");
}

function commentCode() {
  // 实现代码注释逻辑
  console.log("注释代码");
}

document.addEventListener("click", function() {
  var menu = document.getElementById("context-menu");
  menu.style.display = "none";
});