TypeError: $.ajax(...) is not a function?
Double-check if you're using full-version of jquery and not some slim version.
I was using the jquery cdn-script link that comes with jquery. The problem is this one by default is slim.jquery.js which doesn't have the ajax
function in it. So, if you're using (copy-pasted from Bootstrap website) slim version jquery script link, use the full version instead.
That is to say use<script src="https://code.jquery.com/jquery-3.1.1.min.js">
instead of<script src="https://code.jquery.com/jquery-3.1.1.slim.min.js"
Not sure, but it looks like you have a syntax error in your code. Try:
$.ajax({ type: 'POST', url: url, data: postedData, dataType: 'json', success: callback});
You had extra brackets next to $.ajax
which were not needed. If you still get the error, then the jQuery script file is not loaded.