Inconsistency with attributes selectors

[rellect@…]

There is a little inconsistency between Chrome and Firefox with attributes selectors

For the two following examples, chrome could run it, but firefox not:

$('a[rel=nofollow]').on('click', function(event) {
	...
});

$('a[rel=nofollow"]').on('click', function(event) {
	...
});

Firefox stopped the script with error about unrecognized expression.

Finally what worked for both was

$("a[rel='nofollow']").on('click', function(event) {
	...
});

[Rick Waldron]

Yes, quotes are required. Says so in the docs: ​http://api.jquery.com/category/selectors/attribute-selectors/

[dmethvin]

If it's a bare identifier the quotes are optional. But you can't ever half-quote, which seems to be the problem in at least one of them. There's not enough information in the code snippet to know what "could run it" means so it would be best to ask for help on a forum.