How to check if Twitter bootstrap is loaded?

Question

How can I check whether there is a bootstrap.js loaded on page (a file bootstrap.js may be compiled into another big JS file)?

Answer 1

You can retrieve <script> elements and check their src attribute but as you pointed out, what you are looking for is the code itself and not a file name as the code may be in any file.

The best way to detect if a JavaScript service/class/etc. is loaded in a page, is to look for something in the DOM that you know is loaded by the given JS.

E.g. to detect if jQuery is loaded, you can do null !== window.jQuery or to find out the version of the loaded jQuery, jQuery.prototype.jquery

Answer 2

I would rather check for specific bootstrap plugin since modal or tooltip are very common, so

if(typeof($.fn.popover) != 'undefined'){
 // your stuff here
}

or

 if (typeof $.fn.popover == 'function') { 
   // your stuff here
  }

works in both bootstrap versions

Answer 3

Add the bootstrap link and notice the change in h1 tag.