Content encoding when file uploading

Question

Hello,
I'm trying to upload png file using javascript and client object model.
When I use approach from
MSDN article, I get transformed content. So file is not opening.
Is it necessary to use Base64 for encoding the file?
It works well for text files. I succeeded to upload master page so. But when I upload PNG, this encoding corrupts content.

Answer 1

Hello Sohel, thank you!
I use XMLHttpRequest for getting file content:
xhr = new XMLHttpRequest();
 xhr.onreadystatechange = onContentReadStateChange;
 xhr.open("GET", sourceFileURL, true);
 xhr.send();
(may be I should use another approach to read, not to write? I don't want to use JQuery for this)
then I use approach you suggest to put content to base64:
fileContent = xhr.responseText;
fileCreateInfo.set_content(new SP.Base64EncodedByteArray());
        for (var i = 0; i < fileContent.length; i++)
         fileCreateInfo.get_content().append(fileContent.charCodeAt(i));
When I upload such file to library, content is writed transformed and destination file can't be viewed as picture: