Endianness in JavaScript

gistfile1.js

// Endian Differences When Interpreting Binary Data in JavaScript

// Let's make a request for a binary file

var xhr = new XMLHttpRequest();
xhr.open('GET', 'data/m101.fits');
xhr.responseType = 'arraybuffer';
xhr.onload = function() {
  var buffer = xhr.response;
  
  // I'll store some parameters since I know this file well.
  var width = 893;
  var height = 891;
  
  // Image data exists at the byte offset of 14400
  var begin = 14400;
  
  // The (16 bit integer) image data ends at ...
  var end = begin + 2 * width * height;
  
  // Take a slice of those bytes from the array buffer
  var imgBuffer = buffer.slice(begin, end);
  
  // Initialize a typed array using the buffer (this should give me the pixel values)
  var img1 = new Uint16Array(imgBuffer);
  
  // Okay, now let's do it another way
  
  // Create a view using the DataView object
  var view = new DataView(imgBuffer);
  
  // Store the number of pixels
  var pixels = width * height;
  
  // Initialize a typed array of length pixels
  var img2 = new Uint16Array(pixels);
  
  // Loop through calling the DataView method getInt16 on the buffer for each pixel.
  for (var i = 0; i < pixels; i += 1) {
    img2[i] = view.getInt16(2 * i);
  }
  
  // I expected img1 and img2 to be the same, but that's not the case.
  // Initializing the typed array using the array buffer interprets the data
  // as little endian, whereas using the DataView object reads the data as big endian.
  // Is this difference intentional?  Why have this endian mismatch?
  
};
xhr.send();