Monaco Editor

<link rel="stylesheet" data-name="vs/editor/editor.main" href="https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.20.0/min/vs/editor/editor.main.min.css">

<div id="container" style="height:400px;border:1px solid black;"></div>

<script src="https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.20.0/min/vs/loader.min.js"></script>

<script>
require.config({ paths: { 'vs': 'https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.20.0/min/vs' }});

window.MonacoEnvironment = { getWorkerUrl: () => proxy };

let proxy = URL.createObjectURL(new Blob([`
    self.MonacoEnvironment = {
        baseUrl: 'https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.20.0/min'
    };
    importScripts('https://cdnjs.cloudflare.com/ajax/libs/monaco-editor/0.20.0/min/vs/base/worker/workerMain.min.js');
`], { type: 'text/javascript' }));

require(["vs/editor/editor.main"], function () {
    let editor = monaco.editor.create(document.getElementById('container'), {
        value: `function x() {
  console.log("Hello world!");
}`,
        language: 'javascript',
        theme: 'vs-light'
    });
});
</script>

~~DISCUSSION:off~~