Automatically save marks.

autoSetMark.js

// ============================================================ //
// Inside of the PRESERVE Area
// ============================================================ //
//
// * IMPORTANT
// You have to install _scrollet.ks.js in order to use this script.
//

var myMarkKeys = ["1", "2", "3", "4", "5"];
var autoMarkInterval = 5000;

// Import from _scrollet.ks.js.
function findScrollableWindow()
{
    let win;

    try
    {
        win = window.document.commandDispatcher.focusedWindow;
        if (win && (win.scrollMaxX > 0 || win.scrollMaxY > 0))
            return win;

        win = window.content;
        if (win.scrollMaxX > 0 || win.scrollMaxY > 0)
            return win;

        for (let frame in win.frames)
            if (frame.scrollMaxX > 0 || frame.scrollMaxY > 0)
                return frame;
    }
    catch (x)
    {
        win = window.content;
    }

    return win;
}

// Refer the function getCurrentMode in _scrollet.ks.js.
function isViewMode () {
    var ev = { originalTarget : document.commandDispatcher.focusedElement || content.document };

    if (!ev.originalTarget.localName)
        ev.originalTarget = { localName : "" };

    return key.getCurrentMode(ev) == key.modes.VIEW;
}

function getScrolletMarks () {
    return plugins.scrollet.getMarksForWin();
}

function getOldestMarkKey () {
    var oldestTime = Date.now();
    var oldestKey = myMarkKeys[0];

    for (var i = 0; i < myMarkKeys.length; i++) {
        var key = myMarkKeys[i];
        var mark = getScrolletMarks()[key];

        if (!mark || !mark.date) {
            return key;
        }
 
        if (mark.date < oldestTime) {
            oldestTime = mark.date;
            oldestKey = key;
        }
    }

    return oldestKey;
}

function existsSameMark (aX, aY) {
    var win = findScrollableWindow();
    var marks = getScrolletMarks();

    for (var i = 0; i < myMarkKeys.length; i++) {
        var key = myMarkKeys[i];
        var mark = marks[key];
        if (mark) {
            if (mark.scrollX == aX && mark.scrollY == aY) {
                return true;
            }
        }
    }
    return false;
}

function sortMarks () {
    var marks = getScrolletMarks();
    var markArray = [];

    for (var i = 0; i < myMarkKeys.length; i++) {
        var key = myMarkKeys[i];
        var mark = marks[key];
        if (mark) {
            markArray.push(mark);
        }
    }

    markArray.sort(
        function (obj, obj2) {
            return obj2.date - obj.date;
        });
    
    for (i = 0; i < myMarkKeys.length; i++) {
        var key = myMarkKeys[i];
        marks[key] = markArray[i];
    }

    return marks;
}

function autoSetMark () {
    if (isViewMode()) {
        var key = getOldestMarkKey();
        var marks = getScrolletMarks();
        var mark = marks[key];

        var win = findScrollableWindow();
        var x = win.scrollX;
        var y = win.scrollY;

        if (!existsSameMark(x, y)) {

            plugins.scrollet.setMark(key);
        }

        marks = sortMarks();
    }
}

if (setMarkTimer) {
    clearInterval(setMarkTimer);
}

var setMarkTimer = setInterval(autoSetMark, autoMarkInterval);

// autoSetMark ends here.