JavaScript and getElementById for multiple elements with the same ID

I know this is an old question and that an HTML page with multiple identical IDs is invalid. However, I ran into this issues while needing to scrape and reformat someone else’s API’s HTML documentation that contained duplicate IDs (invalid HTML).

So for anyone else, here is the code I used to work around the issue using querySelectorAll:

var elms = document.querySelectorAll("[id='duplicateID']");
 
for(var i = 0; i < elms.length; i++) 
  elms[i].style.display='none'; // <-- whatever you need to do here.