Web/JavaScript/Reference/Global objects/DataView/byteLength

The byteLength accessor property represents the length (in bytes) of this view from the start of its ArrayBuffer or SharedArrayBuffer.

Description

The byteLength property is an accessor property whose set accessor function is undefined, meaning that you can only read this property. The value is established when an DataView is constructed and cannot be changed. If the DataView is not specifying an offset or a byteLength, the byteLength of the referenced ArrayBuffer or SharedArrayBuffer will be returned.

Examples

Using the byteLength property

var buffer = new ArrayBuffer(8);
var dataview = new DataView(buffer);
dataview.byteLength; // 8 (matches the byteLength of the buffer)

var dataview2 = new DataView(buffer, 1, 5);
dataview2.byteLength; // 5 (as specified when constructing the DataView)

var dataview3 = new DataView(buffer, 2);
dataview3.byteLength; // 6 (due to the offset of the constructed DataView)

Specifications

Specification
ECMAScript (ECMA-262)The definition of 'DataView.prototype.byteLength' in that specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
`byteLength`	Chrome Full support 9	Edge Full support 12	Firefox Full support 15	IE Full support 10	Opera Full support 12.1	Safari Full support 5.1	WebView Android Full support 4	Chrome Android Full support 18	Firefox Android Full support 15	Opera Android Full support 12.1	Safari iOS Full support 4.2	Samsung Internet Android Full support 1.0	nodejs Full support 0.10

Legend

Full support: Full support