Cambiar el color de fondo js tinymce

tinyMCE.init(
        mode : "textareas",
        theme : "simple",
        oninit : "postInitWork"
    });

function postInitWork()
{
  var editor = tinymce.get('myEditorid');
  editor.getBody().style.backgroundColor = "#FFFF66";
}
Charming Caribou