Support » Plugin: footnotes » bug: undefined is not an object (evaluating ‘a.browser.mozilla’)

  • Resolved Daniel Pardella



    after the update to WordPress 5.5 we found a bug in the jQuery of the Footnotes plugin. This can be found here:

    var b = a.browser.mozilla ? "DOMMouseScroll" + (a.browser.version < "1.9" ? " mousemove" : "") : "mousewheel";

    console in browser says: undefined is not an object (evaluating ‘a.browser.mozilla’)

    The whole thing becomes especially problematic with a caching plugin when the javascript is merged. This means that, as in our case, a cookie box can no longer be loaded.

    How can the error be turned off? It will probably hit many users with the update to 5.5.

    thx and greetings

    The page I need help with: [log in to see the link]

Viewing 3 replies - 1 through 3 (of 3 total)
  • Plugin Author Lol Zimmerli


    Hello Daniel,

    Yes, we have sen this. It is now under investigations and I hope we can have a fix soon.

    Best regards,

    Plugin Contributor pewgeuges



    In the a.browser property has now checks for its existence since v2.0.0 of this plugin. I’m sad that this issue lasted for so long.

    Upcoming v2.0.4 will natively use jQuery UI, but the tooltip infobox is up and running since v2.0.0 thanks to jQuery UI even in WPv5.5 where many users reported issues.

    Best regards.

    • This reply was modified 11 months, 3 weeks ago by pewgeuges.
    Plugin Contributor pewgeuges



    Thanks for helping draw our attention on this problem raised by jQuery migration.

    On the Footnotes plugin level, the issue has been solved by redacting the jQuery.browser checks in They were basically useless, so their removal shouldn’t make any difference, and in fact doesn’t. Please see the full rationale enumerating all redacted instances in wp-content/plugins/footnotes/js/ (the halfways minified file shipped originally for production).

    The rationale has also been posted 40 minutes ago in response to an almost simultaneous thread on the same topic

    In addition, a scriptloadless mode will be available in upcoming v2.1.1, currently available in a v2.1.1d10 development version at

    Hope this helps.

Viewing 3 replies - 1 through 3 (of 3 total)
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