Available in Chrome 38+ | View on GitHub | Browse Samples
The JavaScript Encoding API allows developers to encode and decode strings using a wide range of character encodings.
The example on this page illustrates decoding data from a file into JavaScript strings.
The code obtains raw binary ArrayBuffer by making an XMLHttpRequest
for a local file. The code then calls TextDecoder.decode() to translate the data
into a string, given the appropriate character encoding.
In a real world scenario, source data might be read from files that predate Unicode or from a legacy database system that only supported a specific character encoding.
if ('TextDecoder' in window) {
// The local files to be fetched, mapped to the encoding that they're using.
var filesToEncoding = {
'utf8.bin': 'utf-8',
'utf16le.bin': 'utf-16le',
'macintosh.bin': 'macintosh'
};
Object.keys(filesToEncoding).forEach(function(file) {
fetchAndDecode(file, filesToEncoding[file]);
});
} else {
ChromeSamples.setStatus('Your browser does not support the Encoding API.');
}
// Use XHR to fetch `file` and interpret its contents as being encoded with `encoding`.
function fetchAndDecode(file, encoding) {
var xhr = new XMLHttpRequest();
xhr.open('GET', file);
// Using 'arraybuffer' as the responseType ensures that the raw data is returned,
// rather than letting XMLHttpRequest decode the data first.
xhr.responseType = 'arraybuffer';
xhr.onload = function() {
if (this.status === 200) {
// The decode() method takes a DataView as a parameter, which is a wrapper on top of the ArrayBuffer.
var dataView = new DataView(this.response);
// The TextDecoder interface is documented at http://encoding.spec.whatwg.org/#interface-textdecoder
var decoder = new TextDecoder(encoding);
var decodedString = decoder.decode(dataView);
ChromeSamples.log(decodedString);
} else {
ChromeSamples.setStatus('Error while requesting', file, this.status);
}
};
xhr.send();
}