viewMode.js

$(document).ready(function () {
    //var view = document.cookie.split(';').map(cookie => cookie.split('=')).reduce((accumulator, [key, value]) => ({ accumulator, [key.trim()]: decodeURIComponent(value) }), {});
    var cookie = document.cookie;
    var i = cookie.indexOf("mode=");
    var mode = cookie.charAt(i + 5);

    function darkMode() {
        $(".darkModeSelector").prop("checked", true);
        $(".style").attr("href", "darkMode.css");
        $(".modeIcon").attr("src", "img/darkmodedark.png");
        $(".scrollup").attr("src", "img/scrollupdark.png");
        $(".sortImg").attr("src", "img/sortdark.png");
        $(".seeAllImg").attr("src", "img/seealldark.png");
        $(".crossImg").attr("src", "img/closedark.png");
    }
    function lightMode() {
        $(".darkModeSelector").prop("checked", false);
        $(".style").attr("href", "style.css");
        $(".modeIcon").attr("src", "img/darkmode.png");
        $(".scrollup").attr("src", "img/scrollup.png");
        $(".sortImg").attr("src", "img/sort.png");
        $(".seeAllImg").attr("src", "img/seeall.png");
        $(".crossImg").attr("src", "img/close.png");
        $(".pubPosts .upPosts").css("color", "black");
    }
    if (mode == 'd') {
        darkMode();
    } else {
        lightMode();
    }
    $(".darkModeSelector").on("change", function () {
        var is_it_checked = $(this).prop("checked");
        if (is_it_checked == true) {
            document.cookie = "mode=d;path=/";
            darkMode();
        } else {
            document.cookie = "mode=l;path=/";
            lightMode();
        }
    });
});