how to use code mirror

codemirror.html

<link rel="stylesheet" href="codemirror-3.16/lib/codemirror.css">
<link href="codemirror-3.16/theme/elegant.css" rel="stylesheet" type="text/css" />
<style type="text/css">
.CodeMirror {border-top: 1px solid black; border-bottom: 1px solid black;}
.CodeMirror {
height: 100%
}
.CodeMirror-scroll {
overflow-y: hidden;
overflow-x: auto;
}
</style>
<script src="codemirror-3.16/lib/codemirror.js"></script>
<script src="codemirror-3.16/mode/xml/xml.js"></script>
<script src="codemirror-3.16/mode/javascript/javascript.js"></script>
<script src="codemirror-3.16/mode/css/css.js"></script>
<script src="codemirror-3.16/mode/htmlmixed/htmlmixed.js"></script>
<script src="codemirror-3.16/mode/htmlembedded/htmlembedded.js"></script>
<script type="text/javascript">
    var editor;
    $(function () {
        editor = CodeMirror.fromTextArea(document.getElementById("fileoutput"), {
            lineNumbers: true,
            matchBrackets: true,
            height: "500px",
            lineWrapping: true,
            indentUnit: 4,
            mode: "application/x-aspx"
        });
    });
</script>