我正在尝试用Codemirror在JavaScript中制作一个代码编辑器。我想要自动完成功能，但它不起作用。有人能告诉我我在这里做错了什么吗。
这是代码：
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>经过大量的研究，比如检查他们的网站示例和其他东西，我终于找到了一个可行的解决方案，下面是代码：
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>