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JavaScript AJAX Basics AJAX Concepts How AJAX Works

Routine Poutine
Routine Poutine
26,050 Points

AJAX: Are callback functions before or after opening the stream?

Hi, Is it better to put the callback function before opening the stream? (I'm not sure if you call this a stream or connection):

I thought the order of AJAX was:

I. Create New XHR Object II. Open Connection III. Event Handler (Callback) IV. Send

const xhr = new XMLHttpRequest();

xhr.open('GET', url, true);

xhr.onload = function() { }


Why is it better to put the callback second?

Best, Matt

1 Answer

Pepe Toño
Pepe Toño
13,815 Points

Hi! As long as you set the 'callback' before the 'send' method is correct, undistinctly if you put it at first or second place on your declaration right before the 'send' method.