Problems with Javascript

Question

Hello, I am programming my site on C9.io and I am using a cont shown here at this link: How to add +1 in a counter variable to each click?

However on C9.io in the line of Js appears $ is not definied, fix it or add global $. When I shoot the $ does not work and when I keep n of certain. How could I fix?

var count = 0;
$('#addCount').click(function(){
  alert(count);
  count++;

          <input type=button id=addCount value="Adicionar Count">

FOLLOWS THE LINK OF THE SITE https://forum-alldispor.c9users.io/index.html#/topics

Answer 1

Try this, now, you could use database to save the Likes! Or a system with files!

var like = $("#likes").text();

$("#addLike").click( function() {
  
$("#likes").text(like++);
  
  
  });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.23/angular.min.js"></script>

<h2>Sistema de likes</h2>

<button class="btn" id="addLike">Like</button>

<h1 id="likes">0</h1>