Thanks for your consideration!
AJAX is called "Asynchronous JavaScript and XML" It can relate to XML where to get the values from any place.
I would explain you again in different way...
This .capx is basic one how to use XML, if you see:
<ball category="RED">
<count>4</count>
<speed>200</speed>
</ball>
Ball Category RED, i didn't implement an event to pick "Category", it's an idea where to pick an object.
Count is 4, it means it could spawn 4 balls, if you change 4 to 10, it will spawn 10 balls.
Speed is 200, it's currently bullet speed for red balls.
If in case AJAX fails, you can add extra events to default values.
I hope you master XML.