*************************************************************
 * casual-markdown-page - view markdown as web page
 * last updated on 2022/12/28, v0.62. 
 *
 * Copyright (c) 2022, Casualwriter (MIT Licensed)
 * https://github.com/casualwriter/casual-markdown
*****************************************************************************/

//=== toggle HTML in right-panel. (this is a hidden function for developer)
function toggleHTML() {
  var html = document.getElementById('right-panel').innerHTML
  if (html.s