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.
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
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