Bootstrap dropdown Jquery Uncaught Error: Syntax error, unrecognized expression

If you are stuck on old Bootstrap then you can patch getParent function of bootstrap-dropdown.js.

Just replace $parent = selector && $(selector) with this:

if (selector && selector !== '#') {
  $parent = $(selector)
}

In my case, I had a script that automatically switches the "active" class on menu items on scroll, all the 'href' of the 'a' html tags under the Boostrap menu must not equal to "#", this solution worked for my case, if anyone has a similar case.

The issue has been fixed by following these steps:

• Use latest version of jQuery v2.1.3 and bootstrap v3.3.6
• Load Bootstrap JS after jquery in order
• Using data-target="#" with href="#" and put the external link on an onClick() trigger.

Hope it helps.