How to show overflowed and scrolled lines outside of editable area?

1

I have an CodeMirror in a page, and I want to make the editable area center(top and bottom areas are not editable). There’s a lot text inside. I want the overflowed text to show outside of the editable area.

I used this but there’s a bug that I can’t use keyboard down arrow or scrollbar to get to the bottom of the page.


<!doctype html>
<html>
<head>
    <script src="lib/codemirror.js"></script>
    <script src="mode/markdown/markdown.js"></script>

	<style>
	.CodeMirror-scroll {
		padding-top: 30px;
		height: calc(100% - 60px) !important;
	}
	</style>

    <link href="lib/codemirror.css" rel="stylesheet">
</head>
<body>
    <div style="width: 350px; border: 2px solid black; ">
        <textarea>Lorem Ipsum is simply dummy text of the printing and typesng industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesng, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesng industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesng, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.Lorem Ipsum is simply dummy text of the printing and typesng industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesng, remaining essentially unchanged. It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum.</textarea>
    </div>
    <script>
    (function () {
        var cm = CodeMirror.fromTextArea(document.querySelector('textarea'), {
            lineWrapping: true,
            mode: 'markdown'
        });
    })()
    </script>
</body>
</html>