sendAsBinary for Google Chrome

The Firefox implementation of XMLHttpRequest has a convenience feature for sending binary data to a server using HTTP POST. The binary data is passed to a method called sendAsBinary as a string with meaningless upper bytes. Javascript has 16-bit strings, so when used to represent binaries each characters has 8 extra bits. A bug had been filed against Google Chrome not having such a method.

I spent some time this evening writing the code that adds a similar method to XHR of Google Chrome, but my implementation should theoretically work with any browser that implements the latest web standards. I did not spend much time testing the code, so it might have bugs in it. It probably is not the most efficient way either. I am just publishing it here in spirit of release early release often.

XMLHttpRequest.prototype.sendAsBinary = function(datastr) {
       var bb = new BlobBuilder();
       var data = new ArrayBuffer(1);
       var ui8a = new Uint8Array(data, 0);
       for (var i in datastr) {
               if (datastr.hasOwnProperty(i)) {
                       var chr = datastr[i];
                       var charcode = chr.charCodeAt(0)
                       var lowbyte = (charcode & 0xff)
                       ui8a[0] = lowbyte;
                       bb.append(data);
               }
       }
       var blob = bb.getBlob();
       this.send(blob);
}