editor.html

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
  <title>Editor</title>
  <style type="text/css" media="screen">
    body {
        overflow: hidden;
    }

    #editor {
        margin: 0;
        position: absolute;
        top: 0;
        bottom: 0;
        left: 0;
        right: 0;
    }
  </style>
</head>
<body>

<pre id="editor">def foo(items):
    for i in len(items):
        print("Ace Rocks", items[i])
</pre>
<script src="https://pagecdn.io/lib/ace/1.4.8/ace.js" crossorigin="anonymous" integrity="sha256-+svOVB1WmhKhTy7N21gWvtyXn91qF0r52P2hIArRRug=" ></script>
<script src="https://pagecdn.io/lib/ace/1.4.8/mode-python.js" crossorigin="anonymous"  ></script>
<script src="https://pagecdn.io/lib/ace/1.4.8/theme-twilight.js" crossorigin="anonymous"  ></script>
<script>
    var editor = ace.edit("editor");
    editor.setTheme("ace/theme/twilight");
    editor.session.setMode("ace/mode/python");
</script>

</body>
</html>