Answers for "add a script in a html doc"

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>

how to link javascript to html

<script src="PathToYourFile.js"> </script>