Want to build a dynamic pricing card. How do I trigger a form input field onChange event?

Design help Custom code
1

I want to allow my visitors to insert their monthly sales which I then use to update the pricing on a set of pricing cards I have on the page.

I am using a Form text input (checked ‘number’) and gave a class of SKFS_PRICING_MRR. When a user updates that form input I want an action to happen. Right now, just trying to get an alert with the value to pop up.

Here is the code I am trying to get work:

<script>
$(document).ready(function() {

 	$('.SKFS_PRICING_MRR').addEventListener("onChange", event => {
		  alert($('.SKFS_PRICING_MRR').value);
         });

});
</script>

I am putting this in the Before tag.

What am I missing? It doesnt seem to work.

Thank you!
~MJP