title: tinymce v4 jquery: how to catch onkeyup?
body: <p>I'm trying to enable submit button when some form fields are filled. I've found a piece of javascript code that works, but I've a problem with textarea fiel which is tranformed by tinymce... How to catch it?</p>
  
  <p>My html:</p>
  
  <pre><code>&lt;form id="form_id1"&gt;
  &lt;fieldset&gt;
  &lt;legend&gt;Personal&lt;/legend&gt;
  Name: &lt;input type="text" size="30" /&gt;&lt;br /&gt;
  Email: &lt;input type="text" size="30" /&gt;&lt;br /&gt;
  Date of birth: &lt;input type="text" size="10" /&gt;&lt;br /&gt;
  Address : &lt;textarea size="30"&gt;&lt;/textarea&gt;&lt;br /&gt;
  
  &lt;/fieldset&gt;
  &lt;input type="submit" value="Submit" /&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>My javascript:</p>
  
  <pre><code>$(document).ready(function()
  {
  
      $('#form_id1 input:submit').attr("disabled", true);
      var textCounter = false;
      $('#form_id1 input:text, #form_id1 textarea').keyup(check_submit);
  
      function check_submit() {
          $('#form_id1 input:text, #form_id1 textarea').each(function()
            {
              if ($(this).val().length == 0) {
                  textCounter = true;
                  return false;
                 }
              else {
                  textCounter = false;
              }
           });
  
          $('#form_id1 input:submit').attr("disabled", textCounter);
      }
  });
  </code></pre>
  
  <p>My tinymce init:</p>
  
  <pre><code>tinymce.init({
                  selector: "textarea",
                  language: 'fr_FR',
                  image_advtab: true,
                  menubar:false,
                  forced_root_block: false,
                  plugins: ["link","code","media","image","textcolor", "emoticons"],
                  toolbar: "bold italic forecolor backcolor alignleft aligncenter alignright alignjustify link unlink image media emoticons",
               });
  </code></pre>
  
  <p>Thanks</p>