XMLHttpRequest: readyState

Baseline

20157

XMLHttpRequest.readyState XMLHttpRequest (XHR) XHR


`0`	`UNSENT`	`open()`
`1`	`OPENED`	`open()`
`2`	`HEADERS_RECEIVED`	`send()`
`3`	`LOADING`	`responseText`
`4`	`DONE`

UNSENT: XMLHttpRequest open()
OPENED: open() setRequestHeader() send()
HEADERS_RECEIVED: send()
LOADING: responseType "text" responseText
DONE

const xhr = new XMLHttpRequest();
console.log("UNSENT", xhr.readyState); // readyState  0 

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

xhr.onprogress = () => {
  console.log("LOADING", xhr.readyState); // readyState  3 
};

xhr.onload = () => {
  console.log("DONE", xhr.readyState); // readyState  4 
};

xhr.send(null);


XMLHttpRequest # states

MDN

MDN 202594

GitHub

XMLHttpRequest API
XMLHttpRequest
1. XMLHttpRequest()
1. readystatechange
1. XMLHttpRequestEventTarget
2. EventTarget
XMLHttpRequest API
1. XMLHttpRequest
2. XMLHttpRequest HTML
5. FormData