$(document).ready(function() {
    var editor = CodeMirror.fromTextArea(document.getElementById('id_content'), {
        mode: 'edx_markdown',
        matchBrackets: true,
        theme: 'default',
        lineWrapping: true,
        keyMap: 'accessible'
    });

  // Store the inital contents so we can compare for unsaved changes
    var initial_contents = editor.getValue();

    window.onbeforeunload = function askConfirm() { // Warn the user before they navigate away
        if (editor.getValue() != initial_contents) {
            return 'You have made changes to the article that have not been saved yet.';
        }
    };

    $('.btn-primary').click(function() {
        initial_contents = editor.getValue();
    });
});