Web/API/ProgressEvent

The ProgressEvent interface represents events measuring progress of an underlying process, like an HTTP request (for an XMLHttpRequest, or the loading of the underlying resource of an <img>, <audio>, <video>, <style> or <link>).

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Constructor

ProgressEvent(): Creates a ProgressEvent event with the given parameters.

Properties

Also inherits properties from its parent Event.

ProgressEvent.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.
ProgressEvent.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.
ProgressEvent.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.

Methods

Also inherits methods from its parent Event.'

ProgressEvent.initProgressEvent() ' ': Initializes a ProgressEvent created using the deprecated Document.createEvent("ProgressEvent") method.

Examples

The following example adds a ProgressEvent to a new XMLHTTPRequest and uses it to display the status of the request.

var progressBar = document.getElementById("p"),
    client = new XMLHttpRequest()
client.open("GET", "magical-unicorns")
client.onprogress = function(pe) {
  if(pe.lengthComputable) {
    progressBar.max = pe.total
    progressBar.value = pe.loaded
  }
}
client.onloadend = function(pe) {
  progressBar.value = pe.loaded
}
client.send()

Specifications

Specification	Status	Comment
XMLHttpRequestThe definition of 'ProgressEvent' in that specification.	Living Standard

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`ProgressEvent`	Chrome Full support 1	Edge Full support 12	Firefox Full support 3.5	IE Full support 10	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 4	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes
`ProgressEvent()` constructor	Chrome Full support Yes	Edge Full support ≤79	Firefox Full support 22	IE No support No	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes
`initProgressEvent` Deprecated'Non-standard'	Chrome No support 1 — 17	Edge No support 12 — 79	Firefox No support 3.5 — 22	IE Full support 10	Opera No support ? — 15	Safari No support ? — ?	WebView Android No support No	Chrome Android No support ? — ?	Firefox Android No support 4 — 22	Opera Android No support ? — 14	Safari iOS No support ? — ?	Samsung Internet Android No support No
`lengthComputable`	Chrome Full support 50	Edge Full support 12	Firefox Full support 3.5	IE Full support Yes	Opera Full support 37	Safari Full support 3.1	WebView Android Full support 50	Chrome Android Full support 50	Firefox Android Full support 4	Opera Android Full support 37	Safari iOS Full support 2	Samsung Internet Android Full support 5.0
`loaded`	Chrome Full support Yes	Edge Full support 12	Firefox Full support 3.5	IE No support No	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 4	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes
`total`	Chrome Full support Yes	Edge Full support 12	Firefox Full support 3.5	IE No support No	Opera Full support Yes	Safari Full support Yes	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 4	Opera Android Full support Yes	Safari iOS Full support Yes	Samsung Internet Android Full support Yes

Legend

Full support: Full support
No support: No support
Non-standard. Expect poor cross-browser support.': Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.': Deprecated. Not for use in new websites.