check if Bootstrap 2 or 3 is enabled

bootstrap_enabled.js

// Bootstrap 3
// Will be true if bootstrap 3 is loaded, false if bootstrap 2 or no bootstrap
var bootstrap3_enabled = (typeof $().emulateTransitionEnd == 'function');
if (!bootstrap3_enabled) {
	document.write('<script src="//netdna.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"><\/script>');
};

// Bootstrap 2-3
// Will be true if bootstrap is loaded, false otherwise
var bootstrap_enabled = (typeof $().modal == 'function');
if (!bootstrap_enabled) {
	document.write('<script src="//netdna.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"><\/script>');
};