javascript:(function(){
 /* Config variables. */
 var heightTakeVideoNotes = /* set initial height for notes */
  "50px";

 /* Global DOM variables */
 var noteAreaTakeNotesIDTakeNotes =  /* parent for note elements */
  document.getElementById("noteAreaTakeNotes");

 var noteBoxTakNotes =               /* textare element for taking notes */
  document.getElementById("noteBoxTakNotes");

 var closeNoteBoxTakeNotes =         /* Close notebox element */
  document.getElementById("closeNoteBoxTakeNotes");

 var aboveTheFoldTakeNotes =         /* html after vidoe box */
  document.getElementById("above-the-fold");

 var playerTakeNotes =               /* video playerTakeNotes topmost parent */
  document.getElementById("player");

 var playButtonTakeNotes =           /* play button - needed to update time mark */
  document.getElementsByClassName("ytp-play-button");

 var currentTimeClassNameTakeNotes = /* class element with current time */
  "ytp-time-current";

 /* Global configuration variables */
 var ignoredKeysTakeNotes =          /* keys pressed that do not active not box */
  "Home End PageUp PageDown";

 var ignoredDOMElementsTakeNotes =   /* stop function if one of these is active */
  ["comments", "search", "contenteditable-root", "player"];

 /* CSS style sheet */
 {
 var noteCSSTakeNotes = `
 /* style close elements with constant styles */
   button[id^="closeBMBtn"] {
    display: inline;
    position: relative;
    left: -5px;
    top: 5px;
    width: 25px;
    height: 25px;
    background: red;
    color: white;
    border: none;
    border-radius: 5px;
    z-index: 1;
   }
   button[id^="closeBMBtn"]:hover,
   button[id^="closeBMBtn"]:hover ~ input[id^="closeBMBtn"]:hover {
    cursor: pointer;
    border: 3px solid gray;
   }
   input[id^="closeBMBtn"] {
    box-sizing: content-box;
    display: inline-block;
    position: absolute;
    left: -5px;
    top: 5px;
    z-index: 2;
    opacity: 0;
   }
   input[id^="closeBMBtn"]:hover {
    cursor: pointer;
    width: 20px;
    height: 20px;
    border: 2px solid gray;
    opacity: .25;
   }

   input[data-close-bm-el^="hide"] + div {
    display: none !important;
   }

   input[data-close-bm-el^="show"] + div#noteArea {
    display: inline-flex;
   }

  /* style note area with constant styles */
  div#noteAreaTakeNotes {
   display: inline-flex;
   flex-wrap: nowrap;
   position: relative;
   top: 0px;
   width: 100%;
  }
  div #noteAreaTakeNotes div {
   display: inline-block;
   position: relative;
   margin: 0px 10px;
   max-width: 450px;
   width: min-content;
  }
  div#noteAreaTakeNotes div+div {
   display: inline-block;
   position: relative;
   max-width: 800px;
   width: auto !important;
   left: 0px;
  }
  /* style note box with constant style */
  textarea#noteBoxTakNotes {
   max-width: 450px;
   width: 450px;
   height: ${heightTakeVideoNotes};
   padding: 10px;
   border-radius: 10px;
  }
`;
  }
 /* Note box setup. */
 var noteTextAreaTakeNotes, noteAreaTakeNotes, noteBoxTakNotesDiv;

 /************************************* SUPPORT FUNCTIONS *************************************/
 /* Create show, hide buttons for elements.  */
 const insertShowHideBtnYouTubeTakeNotes = (el, curId, placeEl, placemnt) => {
  let closeNoteBoxBtn = document.createElement(el);
  closeNoteBoxBtn.id = "closeBMBtn" + curId;
  placeEl.insertAdjacentElement(placemnt, closeNoteBoxBtn);
  closeNoteBoxBtn.textContent = "X";

  /* checkbox to show hide with css */
  let closeCheckbox = document.createElement("input");
  closeCheckbox.type = "checkbox";
  closeCheckbox.id = "closeBMBtnCheckbox" + curId;
  closeNoteBoxBtn.insertAdjacentElement("afterend", closeCheckbox);
  closeCheckbox = document.getElementById("closeBMBtnCheckbox" + curId);
  closeCheckbox.setAttribute("checked", true);
  /* HOT-GLUE */
  if (placeEl.hasAttribute("id") && 
      placeEl.getAttribute("id") == "player") {
   closeCheckbox.style.position = "relative";
   closeCheckbox.style.left = "-30px";
  }

  /* alternate close button status */
  closeCheckbox.addEventListener("mousedown", function() {
   if (this.previousElementSibling.textContent == "X") {
    this.previousElementSibling.textContent = "O";
    /* HOT-GLUE */
    if (placeEl.hasAttribute("id") && 
        placeEl.getAttribute("id") == "player") {
     player.style.display = "none";
    } else {
     this.setAttribute("data-close-bm-el", "hide");
    }
   } else {
    this.previousElementSibling.textContent = "X";
    /* HOT-GLUE */
    if (placeEl.hasAttribute("id") && 
        placeEl.getAttribute("id") == "player") {
     player.style.display = "";
    } else {
     this.setAttribute("data-close-bm-el", "show");
    }
   }
  });
 };

 /* Create note box, ensuring not to duplicate. */
 const addNoteBoxYouTubeTakeNotes = () => {
  if (!noteAreaTakeNotesIDTakeNotes) {
   /* are for notes */
   noteAreaTakeNotes = document.createElement("div");
   noteAreaTakeNotes.id = "noteAreaTakeNotes";
   aboveTheFoldTakeNotes.insertAdjacentElement("beforebegin", noteAreaTakeNotes);

   let noteStyle =         /* using noteCSSTakeNotes from above */
    document.createElement("style");

   noteStyle.textContent = /* add css properties */
    noteCSSTakeNotes;

   noteAreaTakeNotes.insertAdjacentElement("beforebegin", noteStyle);
   noteAreaTakeNotesIDTakeNotes = document.getElementById("noteAreaTakeNotes");

   /* note box */
   noteTextAreaTakeNotes = document.createElement("textarea");
   noteTextAreaTakeNotes.id = "noteBoxTakNotes";
   noteBoxTakNotesDiv = document.createElement("div");

   /* insert div to hold textarea */
   noteAreaTakeNotesIDTakeNotes.insertAdjacentElement("afterbegin", noteBoxTakNotesDiv);

   /* insert textare html elements to take notes */
   noteBoxTakNotesDiv.insertAdjacentElement("afterbegin", noteTextAreaTakeNotes);

   /* close buttnon */
   insertShowHideBtnYouTubeTakeNotes(
     "button",     /* insert button                */
     "NoteBoxBtn", /* set closeBMBtn += NoteBoxBtn */
     noteStyle,    /* placement based on element   */
     "afterend"    /* placement after element      */
   );

   /* close button for video */
   insertShowHideBtnYouTubeTakeNotes(
    "button",        /* insert button                */
    "VideoPlayer",   /* set closeBMBtn += NoteBoxBtn */
    playerTakeNotes, /* placement based on element   */
    "beforebegin"    /* placement before element     */
   );

   /* Redefine noteBoxTakNotes */
   noteBoxTakNotes = document.getElementById("noteBoxTakNotes");
  }
 };

 /* Copy notes in textare to clipboard. */
 const copyNotesTakeNotes = () => {
  noteBoxTakNotes.select();
  navigator.clipboard.writeText(noteBoxTakNotes.value);
 };

 /* Check that another key is not pressed down before moving cursor outside of notebox. */
 const checkKeydownYouTubeTakeVideoNotes = () => {
  if (event.key == "Shift" || event.key == "Control") {
   return true;
  } else {
   return false;
  }
 };

 /* Check if Control and Shift are sequentially keyup and keydown under 1 second. */
 const checkCtrlShiftYouTubeTakeVideoNotes = (ms = 750) => {
  return new Promise(resolve => {
   let ctrlPressed = false;
   let ctrlReleased = false;
   let shiftPressed = false;
   let shiftReleased = false;
   let deadline = 0;
   let timeoutId = null;

   function cleanup(result) {
    document.removeEventListener('keydown', onKeyDown, true);
    document.removeEventListener('keyup', onKeyUp, true);
    if (timeoutId) { clearTimeout(timeoutId); timeoutId = null; }
    resolve(!!result);
   }

   function startTimeout() {
    /* start or restart the timeout for the shift window */
    if (timeoutId) clearTimeout(timeoutId);
    deadline = Date.now() + ms;
    timeoutId = setTimeout(() => {
     /* timed out waiting for shift sequence */
     cleanup(false);
    }, ms);
   }

   function onKeyDown(e) {
    const k = e.key;
    if (k === 'Control') {
     /* ctrl pressed */
     ctrlPressed = true;
    } else if (k === 'Shift') {
     /* only pay attention to shift if ctrl has already been released */
     if (ctrlReleased && !shiftPressed) {
      shiftPressed = true;
     }
    }
   }

   function onKeyUp(e) {
    const k = e.key;
    if (k === 'Control') {
     /* only consider a ctrl "release" if it was pressed first */
     if (ctrlPressed) {
      ctrlPressed = false;
      ctrlReleased = true;
      startTimeout();
     }
    } else if (k === 'Shift') {
     /* only consider shift release if we saw a shift press after ctrl release */
     if (shiftPressed) {
      shiftPressed = false;
      shiftReleased = true;

      /* check timing and that neither key is currently held down */
      const withinTime = Date.now() <= deadline;
      const ctrlStillHeld = ctrlPressed;  /* should be false */
      const shiftStillHeld = shiftPressed; /* should be false */

      if (withinTime && !ctrlStillHeld && !shiftStillHeld) {
       cleanup(true);
      } else {
       cleanup(false);
      }
     }
    }
   }

   /* attach capturing listeners so they catch keys even if elements stop propagation */
   document.addEventListener('keydown', onKeyDown, true);
   document.addEventListener('keyup', onKeyUp, true);

   /* safety: if nothing happens for (ms + 1000) ms, give up */
   const globalTimeout = setTimeout(() => {
    if (timeoutId) { clearTimeout(timeoutId); timeoutId = null; }
    cleanup(false);
   }, ms + 1000);

   /* ensure the safety timeout cleared on final cleanup */
   const origCleanup = cleanup;
   cleanup = function(result) {
    clearTimeout(globalTimeout);
    origCleanup(result);
   };
  });
 };

 /* Focus on textarea whenever keydown occurs. */
 const keypressToNoteTakeNotes = () => {
  let activeID = document.activeElement.id;
  let lastKeyPressTakeNotes; /* used to check for key combos */
  lastKeyPressTakeNotes = sessionStorage.getItem("lastKeyPressTakeNotes");

  /* for first key press */
  if (lastKeyPressTakeNotes == null) {
   sessionStorage.setItem("lastKeyPressTakeNotes", event.key);
   lastKeyPressTakeNotes = sessionStorage.getItem("lastKeyPressTakeNotes");
  }

  /* store key press and check active element */
  let currentKeyPress = event.key;

  /* start conditions to activate note box or run function accordingly  */
  /* if any of these elements have focus */
  /** ignoredDOMElementsTakeNotes = "comments search contenteditable-root playerTakeNotes"; **/
  /* then don't take notes - note - variable defined at start */
  for (i in ignoredDOMElementsTakeNotes) {
   if (activeID == ignoredDOMElementsTakeNotes[i]) {
    /* quit function  */
    return;
   }
  } /* else */
  { /* the active element is not in ignored list, run function */
   let checkKeyCombo = /* check for combos */
    lastKeyPressTakeNotes + "+" + currentKeyPress;
    
   /* check key combos and run function accordingly */
   checkCtrlShiftYouTubeTakeVideoNotes(750).then((ok) => {
    /* checkKeyCombo = "Control Shift" */
    if (ok) {
     noteBoxTakNotes.blur(); 
    } else {
     let skip; /* do nothing */
    }
   });
   /* select and copy notes to clipboard  */
   if (checkKeyCombo == "Alt+a") {
    copyNotesTakeNotes();
   } else {
    /* only if note box is not active element */
    if (activeID != "noteBoxTakNotes") {
     /* prevent fullscreen from occuring *//*
     **************************************
     NOTE - THIS DOES NOT WORK
     *************************
     if (currentKeyPress == "f") {
      document.activeElement.dispatchEvent(new KeyboardEvent('keydown', {'key': 'Esc'}));
     }
     **************************************
     ***************************************/
     /* USE VARIABLE FOR CONDITIONS */
     let noIgnoredKeys = ignoredKeysTakeNotes.indexOf(event.key) == -1;
     let notPauseShortcut = checkKeyCombo != "Shift+ ";
     if (noIgnoredKeys) {
      if (notPauseShortcut) {
       noteBoxTakNotes.focus();
      }
     }
    }
   }
  }
  /* store key press for next key combo check */
  sessionStorage.setItem("lastKeyPressTakeNotes", event.key);
 };

 /* Quickly get back to notes */
 const addKeyDownTakeNotes = () => {
  document.body.addEventListener("keydown", function() {
   keypressToNoteTakeNotes();
  });
 };

 /*********************************************************************************************
                                          MAIN FUNCTION
 *********************************************************************************************/
 function takeVideoNotes() {
  /* add note box */
  addNoteBoxYouTubeTakeNotes();

  /* begin taking notes */
  noteBoxTakNotes.focus();

  /* listen for keydown event */
  addKeyDownTakeNotes();
 }

 /* Call main function. */
 takeVideoNotes();
})();