index.md

title	slug	page-type	browser-compat
XMLHttpRequestUpload: error event	Web/API/XMLHttpRequestUpload/error_event	web-api-event	api.XMLHttpRequestUpload.error_event

{{APIRef}}

The error event is fired when the request encountered an error.

Syntax

Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}}, or set an event handler property.

addEventListener('error', (event) => { })

onerror = (event) => { }

Event type

A {{domxref("ProgressEvent")}}. Inherits from {{domxref("Event")}}.

{{InheritanceDiagram("ProgressEvent")}}

Event properties

In addition to the properties listed below, properties from the parent interface, {{domxref("Event")}}, are available.

• {{domxref("ProgressEvent.lengthComputable", "lengthComputable")}} {{ReadOnlyInline}}
  • : 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.
• {{domxref("ProgressEvent.loaded", "loaded")}} {{ReadOnlyInline}}
  • : 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.
• {{domxref("ProgressEvent.total", "total")}} {{ReadOnlyInline}}
  • : 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

Using the error event

You can use the error event to detect a problem with the upload. For a complete code example that uploads a file and displays a progress bar, see the main {{domxref("XMLHttpRequestUpload")}} page.

// In case of an error we hide the progress bar
// Note that this event can be listened to on the xhr object too
function errorAction(event) {
  progressBar.classList.remove("visible");
  log.textContent = `Upload failed: ${event.type}`;
}
xhr.upload.addEventListener("error", errorAction);

Specifications

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Related events: {{domxref("XMLHttpRequestUpload/loadstart_event", "loadstart")}}, {{domxref("XMLHttpRequestUpload/load_event", "load")}}, {{domxref("XMLHttpRequestUpload/progress_event", "progress")}}, {{domxref("XMLHttpRequestUpload/abort_event", "abort")}}, {{domxref("XMLHttpRequestUpload/loadend_event", "loadend")}}, {{domxref("XMLHttpRequestUpload/timeout_event", "timeout")}}
• {{domxref("XMLHttpRequestUpload")}}