My error console is completely empty when attempting to recreate this issue.

Tested in Firefox 3.6.11 & Firefox 4b6

please use report strict warnings option in firefox, then these warning will show up

Having the same thing.

reopening for review - thanks for the additional information

Having the same thing. +1

None of these warnings are things anyone should care about, since it’s perfectly legitimate to access undefined properties on objects. Strict warnings are red herrings.

I like my code to be as clean as possible. Hence I enable strict warnings for my code. Now with that many messages of jquery my console is bloated with 'red herrings'.

Please ... clean up. it IS legitimate to access an uninitialized variable in C too but it generally is case for errors

I agree with the previous comment. This should be fixed, not ignored.

Please reopen and fix.

I am experiencing the same problem and quite frankly to say something like "None of these warnings are things anyone should care about," is ridiculous, and not in keeping with the high standards we as end users have come to expect from jQuery.

Please sort this out.

wontfix is not acceptable. I use a function "isset" instead of crashing on "undefined". Lazy programing not expected from JQuery.

Unable to debug my code "Break on Next" keeps breaking for JQuery errors.

wontfix is a call for disrespectful comments to the specific programmer (snover).

We're not irresponsible, you simply don't understand a point of view that is not your own.

http://hacks.mozilla.org/2011/01/ecmascript-5-strict-mode-in-firefox-4/

http://www.howtocreate.co.uk/strictJSFirefox.html

How about we reopen this and close it patchwelcome? It seems like there are lots of people willing to fix it who have posted here. If you have fixed this problem, please post a link to your fix, or add a pull request at GitHub. Thanks!

You're right Dave, if someone wants to step up and fix the problem - by all means.

Not ready to jump into the jquery source code myself, but how about checking for frequently missing properties before accessing.

For instance, change:

"f=e?a[c.expando]:null,..."

to:

"f=e&&("expando" in c)?a[c.expando]:null,..."

or, if it makes sense to use a default index when f=e:

"f=e?a[c.safetyCheckIndexProp('expando')]:null,..."

where obj.safetyCheckIndexProp(String nameOfProp) returns a reserved value, like 0, if the property doesn't exist, otherwise, returns the prop value.

Ref: http://www.nczonline.net/blog/2010/07/27/determining-if-an-object-property-exists/

"if ('expando' in c){ //property exists }"

A possible fix is to change the hasData function to :

hasData: function( elem ) {
    elem = elem.nodeType ? (elem[jQuery.expando]?jQuery.cache[ elem[jQuery.expando] ]:null) : elem[ jQuery.expando ];

    return !!elem && !isEmptyDataObject( elem );
	},

It fixes errors generated in forefox(tested on firefox 7.0.1)

Replying to [comment:17 quamis]:

A possible fix is to change the hasData function to :

> hasData: function( elem ) {
>     elem = elem.nodeType ? (elem[jQuery.expando]?jQuery.cache[ elem[jQuery.expando] ]:null) : elem[ jQuery.expando ];
> 
>     return !!elem && !isEmptyDataObject( elem );
> 	},
> 

It fixes errors generated in forefox(tested on firefox 7.0.1)

Then it reveals an like wise error at this line:

id = isNode ? elem[ jQuery.expando ] : elem[ jQuery.expando ] && jQuery.expando;