install codemirror for textareas [added]

HTML

<h2 class="mt10">HTML Codemirror</h2>
<textarea id="text-area-html"></textarea>

<h2 class="mt10">Scripts Codemirror</h2>
<p>for include scripts like css or js, etc. </p>
<textarea id="text-area-scripts"></textarea>

<h2 class="mt10">CSS Codemirror</h2>
<textarea id="text-area-css"></textarea>

Scripts

<!-- CSS -->
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/codemirror.min.css" integrity="sha512-MWdvo/Qqcf4pY1ecQUB1uBn0qLp19U/qJ1Rpp2BDZeuBA7YsFEwkvqR/+aG4BroPiAYDunKJ6X8R/Pmdt3p7oA==" crossorigin="anonymous" />
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/theme/monokai.min.css" integrity="sha512-R6PH4vSzF2Yxjdvb2p2FA06yWul+U0PDDav4b/od/oXf9Iw37zl10plvwOXelrjV2Ai7Eo3vyHeyFUjhXdBCVQ==" crossorigin="anonymous" />

<!-- javascript  -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/codemirror.min.js" integrity="sha512-UZAFKlbB343VyEfCComsVIxp836iYUvHyAuRYFoVN4LTNB6mpM+8EgKW8ymIV2qLZQsIiNdbpmJuA8y6IKzOow==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/mode/xml/xml.min.js" integrity="sha512-XPih7uxiYsO+igRn/NA2A56REKF3igCp5t0W1yYhddwHsk70rN1bbbMzYkxrvjQ6uk+W3m+qExHIJlFzE6m5eg==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/mode/htmlmixed/htmlmixed.min.js" integrity="sha512-IC+qg9ITjo2CLFOTQcO6fBbvisTeJmiT5D5FnXsCptqY8t7/UxWhOorn2X+GHkoD1FNkyfnMJujt5PcB7qutyA==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/mode/css/css.min.js" integrity="sha512-rsFXL+3jYau54xgkx2FtVPo+yRM4vLMEU9VBWl8hZX+t8MEYzGBHeHh5ELv04uthHqix7Dhw2o4KgQ1c+s6dEQ==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/mode/javascript/javascript.min.js" integrity="sha512-+tn2IYnLwD2J9p6Nrn/Dl7ag9lluHA0GAblT/vnMiJV8DU/iDsldgf+9XbEqZUee2ThyDtfmSDb+IDZ9u7jrSA==" crossorigin="anonymous"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/codemirror/5.59.2/mode/php/php.min.js" integrity="sha512-i+JuurEwS1TBFIkaoI0KNhkdiR2yu5nAVdFJ/3Sm3BVbMIkq/1Nv/JsFGUZsqB4VKV6vj1wP5yi1aqyxenx2kw==" crossorigin="anonymous"></script>

Javascript

/* Here is the updated version of the load script */
window.onload = function() {
  window.editor = CodeMirror.fromTextArea(document.getElementById("text-area-html"), {
    mode: 'htmlmixed',
    lineWrapping: true,
    lineNumbers: true,
    theme: 'monokai',
    styleActiveLine: true,
    matchBrackets: true
  });
  window.editor = CodeMirror.fromTextArea(document.getElementById("text-area-scripts"), {
    mode: 'htmlmixed',
    lineWrapping: false,
    lineNumbers: true,
    theme: 'monokai',
    styleActiveLine: true,
    matchBrackets: true
  });
  window.editor = CodeMirror.fromTextArea(document.getElementById("text-area-css"), {
    mode: 'css',
    lineWrapping: true,
    lineNumbers: true,
    theme: 'monokai',
    styleActiveLine: true,
    matchBrackets: true
  });
  window.editor = CodeMirror.fromTextArea(document.getElementById("text-area-javascript"), {
    mode: 'javascript',
    lineWrapping: true,
    lineNumbers: true,
    theme: 'monokai',
    styleActiveLine: true,
    matchBrackets: true
  });
  window.editor = CodeMirror.fromTextArea(document.getElementById("text-area-php"), {
    mode: 'php',
    lineWrapping: true,
    lineNumbers: true,
    theme: 'monokai',
    styleActiveLine: true,
    matchBrackets: true
  });
};