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XMLHttpRequest: progress event

The progress event is fired periodically when a request receives more data.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("progress", (event) => {});

onprogress = (event) => {};

Event type

A ProgressEvent. Inherits from Event.

Event properties

In addition to the properties listed below, properties from the parent interface, Event, are available.

lengthComputable Read only: A boolean flag indicating if the total work to be done, and the amount of work already done, by the underlying process is calculable. In other words, it tells if the progress is measurable or not.
loaded Read only: A 64-bit unsigned integer value indicating the amount of work already performed by the underlying process. The ratio of work done can be calculated by dividing total by the value of this property. When downloading a resource using HTTP, this only counts the body of the HTTP message, and doesn't include headers and other overhead.
total Read only: A 64-bit unsigned integer representing the total amount of work that the underlying process is in the progress of performing. When downloading a resource using HTTP, this is the Content-Length (the size of the body of the message), and doesn't include the headers and other overhead.

Examples

Live example

HTML

html

<div class="controls">
  <input
    class="xhr success"
    type="button"
    name="xhr"
    value="Click to start XHR (success)" />
  <input
    class="xhr error"
    type="button"
    name="xhr"
    value="Click to start XHR (error)" />
  <input
    class="xhr abort"
    type="button"
    name="xhr"
    value="Click to start XHR (abort)" />
</div>

<textarea readonly class="event-log"></textarea>

JavaScript

const xhrButtonSuccess = document.querySelector(".xhr.success");
const xhrButtonError = document.querySelector(".xhr.error");
const xhrButtonAbort = document.querySelector(".xhr.abort");
const log = document.querySelector(".event-log");

function handleEvent(e) {
  log.textContent = `${log.textContent}${e.type}: ${e.loaded} bytes transferred\n`;
}

function addListeners(xhr) {
  xhr.addEventListener("loadstart", handleEvent);
  xhr.addEventListener("load", handleEvent);
  xhr.addEventListener("loadend", handleEvent);
  xhr.addEventListener("progress", handleEvent);
  xhr.addEventListener("error", handleEvent);
  xhr.addEventListener("abort", handleEvent);
}

function runXHR(url) {
  log.textContent = "";

  const xhr = new XMLHttpRequest();
  addListeners(xhr);
  xhr.open("GET", url);
  xhr.send();
  return xhr;
}

xhrButtonSuccess.addEventListener("click", () => {
  runXHR(
    "https://raw.githubusercontent.com/mdn/content/main/files/en-us/_wikihistory.json",
  );
});

xhrButtonError.addEventListener("click", () => {
  runXHR("http://i-dont-exist");
});

xhrButtonAbort.addEventListener("click", () => {
  runXHR(
    "https://raw.githubusercontent.com/mdn/content/main/files/en-us/_wikihistory.json",
  ).abort();
});

Result

Specifications

Specification
XMLHttpRequest Standard # event-xhr-progress
XMLHttpRequest Standard # handler-xhr-onprogress

Browser compatibility

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	WebView Android	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet
`progress_event`	1	12	1	10	≤12.1	3	≤37	18	4	≤12.1	1	1.0