[TYPO3-english] TYPO3.settings.ajaxUrls in custom Backend

[Jennifer Koenig]

Context: AJAX in TYPO3 6.2.5 with custom backend (no Prototype, no ExtJs)

I'm currently trying to set up a form in the backend that needs to use AJAX. When the user clicks a button in the form, data from the form elements should get sent as parameters to an action method in a controller.  As reference I've used the following:

http://docs.typo3.org/typo3cms/CoreApiReference/JavaScript/Ajax/Backend/Index.html

I keep getting the error "ReferenceError: TYPO3 is not defined."  for the following lines of code:

    $.ajax({
	type: "GET",
	url: TYPO3.settings.ajaxUrls['PackageBuilder::checkFlightAvailability'],
	data: { packageData: params }
    })
    .done(function( msg ) {
	alert( "Data Saved: " + msg );
    });

TYPO3.settings.ajaxUrls is supposed to be a global javascript variable. However, I am using a custom backend that does not include Prototype (which just kept messing up ALL of my scripts) or ExtJs. Is this setting defined in one of those libraries?

What do I need to include in my Javascript, or what JS files do I need to include in my backend layout, in order to have TYPO3.settings defined as a global JS variable, as it should be?