Why JS returns $ is not defined?

Question

When I write jQuery code in js, starting with
$(document).ready(function(){
});
the js returns that $ is not defined. How to solve thiss issue?

Answer 1

<scriptsrc="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>

add this in the head tag

Answer 2

yeah it will only work if you refer the jquery library's link in the head tag