Question

I was trying to get data back from an ajax call, and was using the code

jQuery.ajax({
        type: 'POST',
        url: '/chatlog',
        success: exoticlangAjaxCompleted,
        data:'messageLog=' + privateMessageLogJson,
        dataType: 'json'
    });

The data was in a JSON array (key = “messageLog”)

Why did it work to call

    success: exoticlangAjaxCompleted,

but not

    success: exoticlangAjaxCompleted(),

or

    success: exoticlangAjaxCompleted(messageLog) ??

JS function is:

function exoticlangAjaxCompleted(messageLog){
    console.log('exoticlangAjaxCompleted!');
    console.log('chat log is: ' + messageLog);
    console.log('chat log is: ' + dump(messageLog));
}

Answer 1

The success argument expects a reference to function that will be invoked when the AJAX request is complete.

With the following:

success: exoticlangAjaxCompleted,

You are passing a reference to a function as required.

Whereas in this instance:

success: exoticlangAjaxCompleted(),

You are invoking your exoticlangAjaxCompleted function and passing the result to the success argument. Unless your function returns a function, this will not work!