Why my code is not working?

Question

Cant find the error
https://code.sololearn.com/WUf3lKSwNGTW/?ref=app
https://code.sololearn.com/WUf3lKSwNGTW/?ref=app
https://code.sololearn.com/WUf3lKSwNGTW/?ref=app

Answer 1

add this
<script src = "www.ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>

Answer 2

you didn't include the <script> tag mentioning the jquery.js