// Using document.querySelector() to find the span element by its text content -- this did not work.
//var spanElement = document.querySelector('span:contains("Drag items you want to transfer into one of these slots:")');
That's because that's jQuery syntax, check out https://jsfiddle.net/qabxnv0e/ (which also has a slightly fancier way of doing it in pure js).
That's because that's jQuery syntax, check out https://jsfiddle.net/qabxnv0e/ (which also has a slightly fancier way of doing it in pure js).