jQuery should work in Firefox, do you have a specific example of a page that's not working?

Just another question:

The System Details list shows this extension: Buffer 3.3.20 (firefox@buffer)

Do you recognize this extension because otherwise it might be malware?

Thanks for your concern. but I am unable to rectify problem yet. I am attaching images of the console while browsing jquery containing website. eg: www.jquery.com

Is this happening on multiple websites, or just jquery.com? For example, if you go to this page: https://jsfiddle.net/qwchnmha/ , what message do you see in the lower-right (it should say either "no" or "yes")?

it is happening on various websites. also whenever using jquery at offline mode. screenshots are attached below. yes, also on jsfiddle

In your screenshot, it looks like you might have "pause on all exceptions" enabled (the octagon icon with two vertical lines in it is highlighted blue). Could you try clicking that to disable it, or switch it to just "pause on uncaught exceptions"?

I think what's happening is that jQuery does this in order to test whether your browser is an old version of Opera or not:

assert(function( div ) {
	...
			// Opera 10-11 does not throw on post-comma invalid pseudos
			div.querySelectorAll("*,:x");
			rbuggyQSA.push(",.*:");
		});

So it's expected that this code causes an error, since the only browser it works in is Opera. Normally, the assert() block around it would mean that the error gets ignored and that jQuery finishes loading normally, but because you have "pause on all exceptions" enabled, the devtools will stop the page.

Thanks for your concern. I got it.