ProgressEvent: total property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨July 2015⁩.

Note: This feature is available inWeb Workers.

TheProgressEvent.total read-only property is a number indicating the total size of the data being transmitted or processed.

ForProgressEvents dispatched by the browser, the value refers to the size, in bytes, of a resource and is derived from theContent-Length response header.

In aProgressEvent you create yourself, this may also be the total bytes of a resource, although this can be any number.For example, you may wish to normalizetotal to a value such as100 or1 if revealing the precise amount of bytes of a resource is a concern.If using1 as a total, thenProgressEvent.loaded would be a decimal value between0 and1.

If the event'slengthComputable property isfalse, this value is meaningless and should be ignored.