Question

There are many posts about how to fallback a JQuery CDN to a local copy by checking the existance of the global variable JQuery.

My question is , how to do the same to twitter-bootstrap ? Is there a variable defined in bootstrap so that I can check to make sure the CDN is available ?

BTW, I use netdna.bootstrapcdn.com as my bootstrap CDN

Answer 1

I didn’t see a specific variable that twitter-bootstrap exposes for this purpose and they don’t attach all of their plugins to a namespace a la jQuery UI. Your next best bet is to test for one of the bootstrap plugins. Perhaps something like this:

if(typeof($.fn.modal) === 'undefined') {
    //load bootstrap locally
}

The unfortunate thing about this is that it is brittle. If the modal plugin is ever renamed or removed this check would always fail.