esized by mouse
      html: '<div id="my_element" style="padding:10px;font-size:20px;color:darkgray;">Contents will change in 5s</div>'
    });

    // Show window
    frame.show();

    setTimeout(() => {
      // Change contents after 1 second
      // Use $ selector to access to content of frame
      // frame.$('#my_element') represents an element inside the window.

      // set HTML with innerHTML
      frame.$('#my_element').innerHTML = '<span style="color:palevioletred">Contents changed!</span><br>'