Fossil

  if( !document.querySelector('body.fdiff') ){
    /* Don't show the diff toggle button for /fdiff because it only
       has a single file to show (and also a different DOM layout). */
    document.querySelectorAll('table.diff').forEach(addToggle);
  }
  const icm = allToggles.length>1 ? window.fossil.page.diffControlContainer : 0;
  if(icm) {
    const btnAll = D.addClass(D.a("#", "Toggle all diffs"), "button");
    D.append( icm, btnAll );
    btnAll.addEventListener('click', function(ev){
      ev.preventDefault();
      ev.stopPropagation();
      /* Figure out whether we want to show all or hide all: if any diffs are
         toggled off, show all, else hide all. */
      let show = false;

       that the checkbox is to the LEFT of of its label. We store the
       sync-scroll preference in F.storage (not a cookie) so that it
       persists across page loads and different apps. */
    cbSync = D.checkbox(keySbsScroll, F.storage.getBool(keySbsScroll,true));
    D.append(eToggleParent, D.append(
      D.addClass(D.create('span'), 'input-with-label'),
      D.append(D.create('label'),
               cbSync, "Sync side-by-side scrolling")
    ));
    cbSync.addEventListener('change', function(e){
      F.storage.set(keySbsScroll, e.target.checked);
    });
  }
  const useSync = cbSync ? ()=>cbSync.checked : ()=>F.storage.getBool(keySbsScroll,true);