JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE HTML>

<HTML>
<HEAD>
    <title>Cwiczenia</title>
    <meta charset="UTF-8">
    <script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
    <script type="text/javascript" src="main.js"></script>
</HEAD>
<BODY>
<div>
<button id="1">1</button>
<button id="2">2</button>
<button id="3">del 1</button>
<button id="4">del 2</button>
<button id="5">show</button>
    </div>
</BODY>
</HTML>

JavaScript

function main() {
    $("#1").click(function () {
        setCookie("pierwsze", "1", 7);
    });
    $("#2").click(function () {
        setCookie("drugie", "2", 7);
    });
    $("#3").click(function () {
        setCookie("pierwsze","", -1);
    });
    $("#4").click(function () {
        setCookie("drugie","", -1);
    });
    $("#5").click(function () {
        var x = getCookie(pierwsze);
        $("div").append(x);
    });
}
$(document).ready(main());

function setCookie(cname, cvalue, exdays) {
    var d = new Date();
    d.setTime(d.getTime() + (exdays*24*60*60*1000));
    var expires = "expires="+d.toUTCString();
    document.cookie = cname + "=" + cvalue + "; " + expires;
}
function getCookie(cname) {
    var name = cname + "=";
    var ca = document.cookie.split(';');
    for(var i=0; i<ca.length; i++) {
        var c = ca[i];
        while (c.charAt(0)==' ') c = c.substring(1);
        if (c.indexOf(name) != -1) return c.substring(name.length,c.length);
    }
    return "";
}