XMLHttpRequestEventTarget: load event

Available in workers

The load event is fired when an XMLHttpRequest transaction completes successfully.

Syntax

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

addEventListener("load", (event) => { })

onload = (event) => { }

Event type

A ProgressEvent. Inherits from Event.

Examples

Usage with XMLHttpRequest

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>

.event-log {
  width: 25rem;
  height: 4rem;
  border: 1px solid black;
  margin: 0.5rem;
  padding: 0.2rem;
}

input {
  width: 11rem;
  margin: 0.5rem;
}

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("image.jpg");
});

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

xhrButtonAbort.addEventListener("click", () => {
  runXHR("image.jpg").abort();
});

Result

Usage with XMLHttpRequestUpload

You can use the load event to detect the successful termination of an upload. For a complete code example that uploads a file and displays a progress bar, see the main XMLHttpRequestUpload page.

// When the upload is finished, we hide the progress bar.
xhr.upload.addEventListener("load", (event) => {
  progressBar.classList.remove("visible");
  log.textContent = "Upload finished.";
  abortButton.disabled = true;
});

Specifications

Browser compatibility

See also

• Related events: loadstart, loadend, progress, error, abort
• Monitoring progress