I would like to write a javascript program to monitor a given web page (like a shopify page) and create an alert when a change is detected.

What is the simplest way to implement this in Javascript? Is there any one library that provides tools to monitor page changes? Ideally, this program could run continuously on my computer and create a notification on my phone.

For the phone notification part, I was thinking I could just use a whatsapp Bot to send a text to my phone