byteLength Property (ArrayBuffer)
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byteLength Property (ArrayBuffer)


Read-only. The length of the ArrayBuffer (in bytes).

var arrayLength = arrayBuffer.byteLength;


The following example shows how to get the byte length of the ArrayBuffer.

var req = new XMLHttpRequest();'GET', "");
    req.responseType = "arraybuffer";

    req.onreadystatechange = function () {
        if (req.readyState === 4) {
            var buffer = req.response;



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.

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