textareas_to_medium_editor.js

// Turns all textareas into medium-editors
// requires: 
//  - Medium-Editor
//  - jQuery (can be easily rewritten without)
//  - find_with_mutations: https://gist.github.com/hampei/7620643
//  - sync_node_html_to_form_field: https://gist.github.com/hampei/7620825
window.textareas_to_medium_editor = function() {
  find_with_mutations('form', 'textarea', function(el) {
    el.style.display = 'none'; // hide the textarea
    editor = $('<div />');     // create editor element
    editor.html(el.value);     // initialize editor with value
    $(el).after(editor);       // insert the editor
    sync_node_html_to_form_field(editor[0], el); // sync editor to the textarea
    new MediumEditor(editor);
  })
}