Which Method Will Make The Page Load Faster - Calling Code From A .js File 50 Times Slow Down Page Load?

I have a single webpage that contains information on all 50 U.S. states. There are 50 links at the top to jump down to the state you want, and at the bottom of the information for each state a Back to Top link.

I'm making the Back to Top link into something more complex, and it will require three or four lines of code.

So that I don't have to repeat the code 50 times, and create a burden when I need to edit it, I want to place it in a .js file and call it x. Then below the information for each state I'll simply have:

Does calling code from a .js file 50 times slow down the page load? Which method would load faster?