TypeError: $.ajax(…) is not a function?

Question

I'm trying to create a simple AJAX request which returns some data from a MySQL database. Here's my function below:

function AJAXrequest(url, postedData, callback) {
    $.ajax() ({
        type: 'POST',
        url: url,
        data: postedData,
        dataType: 'json',
        success: callback
    });
}

...and here's where I call it, parsing in the required parameters:

AJAXrequest('voting.ajax.php', imageData, function(data) {
    console.log("success!");
});

Yet, my success callback does not run (as "success!" is not logged to the console), and I get an error in my console:

TypeError: $.ajax(...) is not a function.
success: callback

What does this mean? I've done AJAX requests before where the success event triggers an anonymous function inside of $.ajax, but now I'm trying to run a separate named function (in this case, a callback). How do I go about this?

Answer 1

There is a syntax error as you have placed parenthesis after ajax function and another set of parenthesis to define the argument list:-

As you have written:-

$.ajax() ({
    type: 'POST',
    url: url,
    data: postedData,
    dataType: 'json',
    success: callback
});

The parenthesis around ajax has to be removed it should be:-

$.ajax({
    type: 'POST',
    url: url,
    data: postedData,
    dataType: 'json',
    success: callback
});

Answer 2

I encountered the same question, and my solution was: add the JQuery script.

Especially, we should make sure the corresponding JQuery is loaded when we debug our js under the firefox/chrome.

Answer 3

Reference the jquery min version that includes ajax:

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.min.js"></script>

Answer 4

You have an error in your AJAX function, too much brackets, try instead $.ajax({

Answer 5

Neither of the answers here helped me. The problem was: I was using the slim build of jQuery, which had some things removed, ajax being one of them.

The solution: Just download the regular (compressed or not) version of jQuery here and include it in your project.

Answer 6

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.