Codemirror autocomplete doesn't work for javascript

I am trying to make a code editor in JavaScript with Codemirror. I want the autocomplete feature, but it doesn't work. Can someone please tell me what I am doing wrong here.

Here is the code :

var editor = CodeMirror.fromTextArea(myTextarea, {
  lineNumbers: true,
  extraKeys: {
    "Tab": "autocomplete"
  },
  hint: CodeMirror.hint.javascript
});

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <script src="https://codemirror.net/lib/codemirror.js"></script>
  <script src="https://codemirror.net/mode/javascript/javascript.js"></script>
  <script src="https://codemirror.net/addon/hint/show-hint.js"></script>
  <script src="https://codemirror.net/addon/hint/anyword-hint.js"></script>
  <link rel="stylesheet" href="https://codemirror.net/lib/codemirror.css">
  <link rel="stylesheet" href="https://codemirror.net/addon/hint/show-hint.css">
  <title>Code</title>
</head>

<body>
  <textarea name="myTextarea" id="myTextarea" cols="30" rows="10"></textarea>

  </script>

Solution

After a ton of research, like checking their site example and stuff, I finally found a working solution, here is the code:

 var editor = CodeMirror.fromTextArea(myTextarea, {
    lineNumbers: true,
    extraKeys: {"Ctrl-Space": "autocomplete"},
    mode: {name: "javascript", globalVars: true}
  });

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <link rel="stylesheet" href="https://codemirror.net/lib/codemirror.css">
  <link rel="stylesheet" href="https://codemirror.net/addon/hint/show-hint.css">
  <script src="https://codemirror.net/lib/codemirror.js"></script>
  <script src="https://codemirror.net/addon/hint/show-hint.js"></script>
  <script src="https://codemirror.net/addon/hint/javascript-hint.js"></script>
  <script src="https://codemirror.net/mode/javascript/javascript.js"></script>
  <script src="https://codemirror.net/mode/markdown/markdown.js"></script>
  <title>Code</title>
</head>

<body>
  <textarea name="myTextarea" id="myTextarea" cols="30" rows="10"></textarea>
</body>

</html>