When using AJAX, which HTTP method is commonly used to send data to the server?

The choice of the POST method is typically the most common approach when sending data to the server using AJAX. This is because POST is specifically designed for sending data in the request body, making it ideal for forms, file uploads, and any other data submissions where the content of the request needs to be conveyed clearly to the server.

When utilizing AJAX, there is often a requirement to submit larger amounts of data or sensitive information. The POST method allows for this, as it can handle substantial payloads and does not append data to the URL like GET does. Additionally, POST requests can create or update resources on the server, which aligns with many use cases in web applications.

GET, while also a method used in AJAX for retrieving data, is not typical for sending data to the server since it appends the data as query parameters in the URL and is limited in size. PUT and DELETE methods serve specific purposes for updating and deleting resources, respectively, but are less common for general data submissions in AJAX scenarios.

Thus, POST is the optimal choice for sending data due to its versatility and ability to handle larger and more secure data transmissions.