Ever since WordPress 4.5 rolled off the press there have been numerous complaints about websites breaking. Numerous reports are coming into our Store Locator Plus forums and support email telling us “our map broke when they updated our website”. The problem? jQuery. To be more specific the problem is not jQuery but how some plugins and themes implement jQuery in WordPress.
WordPress 4.5 started shipping jQuery version 1.12.3 as the “official” version of jQuery being used with WordPress core. jQuery 1.12 has more stringent controls than previous versions. The most obvious, jQuery 1.12 no longer “hides” some of the syntax errors that lay dormant in plugin code. If there is malformed or incorrect syntax, jQuery 1.12 will complain. Your browser will most likely stop executing ALL scripts from that point forward. As you can imagine, this causes things, like themes and plugins to break.