$.contains fatal error in IE9 when 2nd parameter is null

[konp]

Summary

Calls to $.contains fail when parameter is null, breaks all scripts.

Reason

The reason for failure is that when element.compareDocumentPosition is called with null in IE9 it returns invalid argument. Returns false in Chrome as expected.

jQuery Version: 1.8.0

Browser: IE9 RTM

jsFiddle:  http://jsfiddle.net/Zj8VQ/

[dmethvin]

1) Is there some place within jQuery that calls $.contains with the second arg of null? Or was this a direct use inside your own code?

2) DO NOT TAUNT HAPPY FUN $.CONTAINS!

[konp]

Replying to dmethvin:

1) Is there some place within jQuery that calls $.contains with the second arg of null? Or was this a direct use inside your own code?

From within jQuery UI animations callback to removeWrapper() function - the document.activeElement is used as the second parameter. In IE9, active element can be null (such is the case with certain animations and calls to .blur()). Although I found this bug by using jQuery UI, I am considering this a bug in jQuery as it is a breaking change between 1.7.2 and 1.8.0. Again, please look at the same code working with 1.7.2 -  http://jsfiddle.net/Zj8VQ/1

EDIT: In Chrome, activeElement returns body instead of null.

2) DO NOT TAUNT HAPPY FUN $.CONTAINS!

SRR

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Either way, the expected behavior should be the same across browsers.

[Timmy Willison]

Update Sizzle: passing null to $.contains should not throw an error. Fixes #12314

Changeset: 2be615eaa16a5916d0a194e3c2f6bc2a2d62b236