For simple transition effects, include
transition.js once alongside the other JS files. If you're using the compiled (or minified)
bootstrap.js, there is no need to include this—it's already there.
Transition.js is a basic helper for
transitionEnd events as well as a CSS transition emulator. It's used by the other plugins to check for CSS transition support and to catch hanging transitions.
bootstrap.min.js, as the case may be) has loaded: