Answers for "how to link a js file in a html file"

kill all server 5000 mac

#First run this, to get port information (with the port you want to kill)
sudo lsof -i :3000 

#Then run this, with <PID> replaced by the value in the column returned by previous command.
kill -9 <PID>

mac terminal find process by port

sudo lsof -i tcp:3000

mac process on port

lsof -i tcp:3000

killing a port mac

sudo lsof -i :3000

find which process is using port mac

sudo lsof -i tcp:3001

import js in html

<script type="text/javascript" src="yourfile.js"></script>