An EventHandler
that is called whenever the readyState
attribute changes. The callback is called from the user interface thread. The XMLHttpRequest.onreadystatechange
property contains the event handler to be called when the readystatechange
event is fired, that is every time the readyState
property of the XMLHttpRequest
changes.
Warning: This should not be used with synchronous requests and must not be used from native code.
Syntax
XMLHttpRequest.onreadystatechange = callback;
Values
callback
is the function to be executed when thereadyState
changes.
Examples
const xhr = new XMLHttpRequest(), method = "GET", url = "https://developer.mozilla.org/"; xhr.open(method, url, true); xhr.onreadystatechange = function () { // In local files, status is 0 upon success in Mozilla Firefox if(xhr.readyState === XMLHttpRequest.DONE) { var status = xhr.status; if (status === 0 || (status >= 200 && status < 400)) { // The request has been completed successfully console.log(xhr.responseText); } else { // Oh no! There has been an error with the request! } } }; xhr.send();
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 | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
onreadystatechange | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 5 | Opera Full support 9 | 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 |
Legend
- Full support
- Full support