I am getting a file "abc.txt" from server and dispaying it in a text area for editing. <div id="filecontents"> <textarea> CONTENTS OF FILE LARGER THAN 10KB </textarea> </div> The contents of the file are potentially large. The user will edit the textarea and add/delete text from any part(not just the end). I want to send ONLY the changes to the server for patching. How do I accomplish this?. Is there a javascript version of the popular linux command(diff). John Resig's diff code may not work as, for me, it will involve additional parsing on server side. Thanks!