Web/API/XMLHTTPRequest/readyState

The XMLHttpRequest.readyState property returns the state an XMLHttpRequest client is in. An XHR client exists in one of the following states:

Value	State	Description
0	UNSENT	Client has been created. open() not called yet.
1	OPENED	open() has been called.
2	HEADERS_RECEIVED	send() has been called, and headers and status are available.
3	LOADING	Downloading; responseText holds partial data.
4	DONE	The operation is complete.

UNSENT

The XMLHttpRequest client has been created, but the open() method hasn't been called yet.

OPENED

open() method has been invoked. During this state, the request headers can be set using the setRequestHeader() method and the send() method can be called which will initiate the fetch.

HEADERS_RECEIVED

send() has been called and the response headers have been received.

LOADING

Response's body is being received. If responseType is "text" or empty string, responseText will have the partial text response as it loads.

DONE

The fetch operation is complete. This could mean that either the data transfer has been completed successfully or failed.

The state names are different in versions of Internet Explorer earlier than 11. Instead of UNSENT, OPENED, HEADERS_RECEIVED, LOADING and DONE, the names READYSTATE_UNINITIALIZED (0), READYSTATE_LOADING (1), READYSTATE_LOADED (2), READYSTATE_INTERACTIVE (3) and READYSTATE_COMPLETE (4) are used.

Example

var xhr = new XMLHttpRequest();
console.log('UNSENT', xhr.readyState); // readyState will be 0

xhr.open('GET', '/api', true);
console.log('OPENED', xhr.readyState); // readyState will be 1

xhr.onprogress = function () {
    console.log('LOADING', xhr.readyState); // readyState will be 3
};

xhr.onload = function () {
    console.log('DONE', xhr.readyState); // readyState will be 4
};

xhr.send(null);

Specifications

Specification	Status	Comment
XMLHttpRequest	Living Standard	WHATWG living standard

Browser compatibility

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
readyState	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 7	Opera Full support 8	Safari Full support 1.2	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 10.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0
constants	Chrome Full support Yes	Edge Full support 12	Firefox Full support 9	IE Full support 9	Opera Full support 12	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support 18	Firefox Android Full support 9	Opera Android Full support Yes	Safari iOS ?	Samsung Internet Android Full support 1.0

Legend

Full support  

Full support

Compatibility unknown  

Compatibility unknown

XMLHttpRequest.readyState by Mozilla Contributors is licensed under CC-BY-SA 2.5.