AJAX stands for “Asynchronous JavaScript and XML”. Although the name includes XML, JSON is more often used due to it’s simpler formatting and lower redundancy. AJAX allows the user to communicate with external resources without reloading the web page.

AJAX stands for Asynchronous JavaScript and XML. Nevertheless you can actually use other types of data and—in the case of [tag:XMLHttpRequest]—switch to the deprecated synchronous mode.

AJAX allows web pages to send HTTP requests to the server and receive a response, without needing to reload the entire page.

Sending and Receiving JSON Data via POST

AJAX preloader

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Using GET with parameters

Check if a file exists via a HEAD request

Using GET and no parameters

Listening to AJAX events at a global level