var is maximally compatible with older browsers. let and const are more tightly scoped, and that can help you write more maintainable code. I think maintainabi

var is maximally compatible with older browsers. let and const are more tightly scoped, and that can help you write more maintainable code. I think maintainability was not a first class concern in the writing of this script (consider the terse naming of variables), but it doesn't really matter; it's short, and you can understand it all because there's not all that much to understand. It does the job, and works everywhere.