1. jquery demo

Step by Step - Vue.js

by Rahul Kadyan

HTML

<script src="//unpkg.com/jquery"></script>

<div id="app">
  <button id="dec" type="button">-</button>
  <span id="val">0</span>
  <button id="inc" type="button">+</button>
</div>

CSS

html {
  font-size: 24px;
}

JavaScript

$(document).ready(function() {
  const $val = $('#val')
  let val = 0

  $('#dec').click(() => {
    --val

    $val.text(val)
  })

  $('#inc').click(() => {
    ++val

    $val.text(val)
  })
});