byteLength Property (DataView)
Read-only. The length of this view from the start of its ArrayBuffer, in bytes, as fixed at construction time.
The following example shows how get the length of a DataView from an XMLHttpRequest.
Supported in the following document modes: Internet Explorer 10 standards and Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information. Not supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards.