XMLHttpRequest: readystatechange event
The readystatechange
event is fired whenever 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
Use the event name in methods like addEventListener()
, or set an event handler property.
addEventListener('readystatechange', event => { })
onreadystatechange = event => { }
Event type
A generic Event
with no added properties.
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 |
---|
XMLHttpRequest Standard # event-xhr-readystatechange |
XMLHttpRequest Standard # handler-xhr-onreadystatechange |
Browser compatibility
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