HTML : Uncaught reference error: $ is not defined error

HTML : Uncaught reference error: $ is not defined error
To Access My Live Chat Page,
On Google, Search for "hows tech developer connect"

As promised, I'm going to share a hidden feature with you.
This is a YouTube's feature which works on Desktop.
First, Make sure this video is playing.
Next, enter the letters 'awesome' on your keyboard.
You will see a flashing rainbow instead of a regular progress bar on YouTube.

Here's a short introduction about myself,
Hello there, my name is Delphi.
Allow me to support you in answering your questions.
HTML : Uncaught reference error: $ is not defined error
Don't hesitate to leave a comment or start a chat if you have a more specific question.
Your thoughts and contributions are welcome, so please leave a comment below if you have an answer or insights to the answer.
A 'heart' from me will indicate my appreciation for your answer.
is : not reference defined error: Uncaught $ error HTML