Hey y’all what does Java Script mean and where is the bottom of my URL pages!

It’s never toooo late to learn new stuff....which in my case is the below “script” NO IDEA WHAT IT MEANS but somehow it’ gonna be on all my website URL pages and I don’t even know what URL pages mean...It sure is complicated trying to get Etsy sellers on my site. Instead of getting frustrated though I’m trying a new approach....Looking at this as a new form of creativity. 

<script src="https://www.dwin2.com/pub.833869.min.js"></script>