How to fix IE9 debugging error pointing to jQuery 3.3.* file?

Question

JavaScript

When debugging in IE, errors are displayed in two places SyntaxError, I seem to have read it on the Internet, but I still don’t understand what kind of error it is and why it appears, and also what should I do with it?

el.querySelectorAll("*,:x")

matches.call( el, "[s!='']:x" );

Answer 1

jQuery should work in IE9. There are definitely no syntax errors in the code snippets you provided (but for the future, it is better to include a few more lines before and after the place where the error occurs).
I think it's worth looking in your code, as it happened that IE can point to the wrong line at all where there are really errors. If the SyntaxError doesn't occur in newer browsers, then you've probably used some of the new JavaScript syntax, such as const, let rest parameters, arrow functions, classes, and so on.