JSFiddle - React, Tailwind, and code Playground

HTML

<div id="storage">
    <input type="text" id="mail" />
    <button class="store">store</button>
    <button id="reset">reset</button>
    <button id="show">show</button>
</div>

JavaScript

$(document).ready(function () {

    $(".store").on("click", function () {
        var mailaddress = localStorage.getItem("mailaddress");
        var obj = [];
        if (mailaddress) {
            obj = JSON.parse(mailaddress);
        }
        var id = obj.length + 1; // increment the id
        var mail = $('#mail').val(); // get the textbox value
        obj.push({ // push it to obj
            "id": id,
            "mail": mail
        });
        localStorage.setItem("mailaddress", JSON.stringify(obj));
    });

    $("#show").on("click", function () {
        var item = JSON.parse(localStorage.getItem("mailaddress"));
        alert(item);
        console.log(item);
    });
    $('#reset').click(function () {
        localStorage.clear();
    });
});