Update README.md

Author: SamMousa

README.md

@@ -2,3 +2,9 @@ jquery-blob
 ===========
 
 Blob support for jQuery ajax.
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+This file is a modified version from https://github.com/jquery/jquery/blob/master/src/ajax/xhr.js
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+When using the blob as dataType argument for the .ajax call (and probably the other AJAX functions) the complete callback will contain the Blob.
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+Can be used in combination with the FileSaver interface to download files via AJAX.