Vanilla script

This function gets the cookie specified:-

function gcook(cookieName) {
        /**
         * This variable holds the array of available cookies
         */
        var cookies = document.cookie.split(";");
        cookieName += "=";
        for (var i = 0; i < cookies.length; i++) {
            var c = cookies[i].trim();
            if (c.indexOf(cookieName) == 0) {
                /**
                 * This statement retrieves the value of the specified cookie
                 */
                return c.substring(cookieName.length, c.length);
            }
        }
        return null;
    }




This function sets a cookie with specified name, value and for certain time:-

    function scook(cookie) {
        var exdate = new Date();
        /**
         * This statement sets the date when the cookie will be removed from the client machine
         */
        exdate.setDate(exdate.getDate() + cookie.time);
        var c_value = cookie.value + (cookie.time == null ? "" : ";expires=" + exdate.toUTCString());
        document.cookie = cookie.name + "=" + c_value;
    }





This function scrolls the document to the top within specified time in ms:-

    function scrollToTop(duration) {
        /**
         * This variable holds the scrolling steps which will be scrolled upto each the the specified duration is reached and the whole page is scrolled to the top within the specified duration
         */
        var scroll = -window.scrollY / ((duration / 15));
        var tID = setInterval(function () {
            if (window.scrollY > 0) {
                window.scrollBy(0, scroll);
            } else {
                /**
                 * This statement stops the further code repetition as the page is being successfully scrolled to the very top
                 */
                clearInterval(tID);
            }
        }, 15);
    }
 

Here is a method using AJAX for form submission in javascript:-

var ajax={}, message={
    "output": null, 
    "error": null,
    "state": null,
    "loaded": 0,
    "total": 0
};
ajax.defaultSettings={
    method: "GET",
    url: "",
    data: [],
    async: true,
    percentageID: "percentage",
    contentType: "application/x-www-form-urlencoded",
    onprogress: function(message){
        return false;
    },
    onsuccess: function(message){
        return false;
    },
    onerror: function(message){
        return false;
    }
}
function AJAX(settings){
    var info="";
    if(settings.method==null){
        settings.method=ajax.defaultSettings.method;
    }
    settings.method=settings.method.toUpperCase();
    if(settings.method!=="GET" && settings.method!=="POST"){
        throw "Please specify a valid method for ajax request";
    }
    if(settings.url==null){
        throw "Please specify the URL to which the request has to be sent";
    }
    if(settings.data==null){
        throw "Please specify the data you want to send";
    }
    if(settings.percentageID==null){
        settings.percentageID=ajax.defaultSettings.percentageID;
    } else{
        ajax.defaultSettings.percentageID=settings.percentageID;
    }
    if(settings.async==null){
        settings.async=ajax.defaultSettings.async;
    }
    if(settings.contentType==null){
        settings.contentType=ajax.defaultSettings.contentType;
    }
    var data, elems;
    elems=Object.keys(settings.data).length
    for(data in settings.data){
        info+=data+"="+encodeURIComponent(settings.data[data]);
        if(elems>1)
            info+="&";
        elems--;
    }
    var handler;
    if(window.XMLHttpRequest){
        handler=new XMLHttpRequest();
    } else{
        handler=new ActiveXObject("Microsoft.XMLHTTP");
    }
    message.state=handler.readyState;
    handler.addEventListener("progress", updateProgress, false);
    if(settings.async==true){
        handler.onreadystatechange=function(){
            if(handler.readyState==4 && handler.status==200){
                message.output=handler.responseText;
                message.error=null;
                message.state=4;
                handler.onsuccess=settings.onsuccess(message);
            } else if(handler.readyState==4 && handler.status==404){
                message.output=null;
                message.error="Page Not Found";
                message.state=4;
                handler.onerror=settings.onerror(message);
            }
        }
    }
    if(settings.method==="GET"){
        handler.open("GET", settings.url+"?"+info, settings.async);
        handler.send();
    } else{
        handler.open("POST", settings.url, settings.async);
        handler.setRequestHeader("Content-type", settings.contentType);
        handler.setRequestHeader("Content-length", info.length);
        handler.setRequestHeader("Connection", "Close")
        handler.send(info);
    }
}
function updateProgress(event){
    message.loaded=event.loaded;
    message.total=event.total;
    settings.onprogress(message);
}

Here is how you can use your custom query selector in javascript:-

window.$=function(selector){
            return document.querySelector(selector);
        }