What functions does ajax have?

ajax functions include XMLHttpRequest(), open(), send(), setRequestHeader(), getResponseHeader(), getAllResponseHeaders(), onreadystatechange, readyState, status, responseText, responseXML, statusText and onerror, etc.

The operating system for this tutorial: Windows 10 system, DELL G3 computer.

In web development, AJAX (Asynchronous JavaScript and XML) is a technology that uses several technologies to allow data to be exchanged with the server through asynchronous requests without refreshing the entire page. In JavaScript, you can use a variety of functions and methods to implement AJAX requests. The following are some common AJAX-related functions:

1. XMLHttpRequest(): This is the constructor that creates an XMLHttpRequest object and is used to send AJAX requests.

2. open(): This method is used to set the URL of the AJAX request, the request type, whether it is processed asynchronously, and the data to be sent to the server.

3. send(): This method is used to send AJAX requests. It accepts one parameter, the data to send to the server.

4. setRequestHeader(): This method is used to set the custom value of the HTTP request header. For example, you can set header information such as Content-Type and Authorization.

5. getResponseHeader(): This method is used to obtain the specific value of the response header returned by the server.

6. getAllResponseHeaders(): This method is used to obtain all response header information returned by the server.

7. onreadystatechange: This is an event handler that will be triggered when the status of the AJAX request changes. When the request completes, the status of the request can be determined by checking the readyState property, and the response data can be accessed.

8. readyState: This is a property used to obtain the status of AJAX requests. It has five possible values: 0 means the request is not initialized, 1 means the request has a connection established, 2 means the request has been sent, 3 means the response is being received, and 4 means the request is complete and the response is ready.

9. status: This is an attribute used to obtain the HTTP status code returned by the server. For example, 200 means success and 404 means resource not found.

10. responseText: This is an attribute used to obtain the response text data returned by the server.

11. responseXML: This is an attribute used to obtain the response XML data returned by the server.

12. statusText: This is an attribute used to obtain the HTTP status text returned by the server.

13. onerror: This is an event handler that will be triggered when an error occurs in the AJAX request.

In addition to the above functions and methods, there are also some other commonly used AJAX-related functions and technologies, such as using fetch() API, using Promise and async/await, etc. These functions and techniques can be used to simplify AJAX development, improve performance, and reduce code size.

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