File comparison in php( like google doc)

My working project details as follows: Admin can add account no from admin section, then admin can create new file for any added account no. That account is basically used for assign to user. In frontend user login with acc no, username and password, after login user can view/edit files which assigned by admin.? Now user can edit and then save that file, in every time of save file, it creates file history of previous version.? So user can view all history versions of file. There is check box of every history version, user selects any two checkbox and click on compare button, it shows the comparison of both histories. My previous developer make that file comparison script but that not work properly, it should be compare similar to google docs file comparison. I am looking some one who can correct that script or make new one script for file comparison. ## Deliverables Project details: Basically I need similar script as google docs file comparison in PHP, in google docs when any user create any document, google maintain that file history in every time of edit and save that document and user can compare history version. If you open any document in google docs in edit mode then there is a menu Tools->Revision History, it shows all history version of file changes and you compare history version also. My working project details as follows: Admin can add account no from admin section, then admin can create new file for any added account no. That account is basically used for assign to user. In frontend user login with acc no, username and password, after login user can view/edit files which assigned by admin.? Now user can edit and then save that file, in every time of save file, it creates file history of previous version.? So user can view all history versions of file. There is check box of every history version, user selects any two checkbox and click on compare button, it shows the comparison of both histories. My previous developer make that file comparison script but that not work properly, it should be compare similar to google docs file comparison. I am looking some one who can correct that script or make new one script for file comparison. I am attaching my running source code and database dump, so every one can view coding pattern. My running project URL details as mentioned below: Frontend: <[login to view URL]> acc no: ACC001, username: user, password: pass Admin <[login to view URL]> username/password: admin/admin Script should be compatible with running source code and after complete job coder should to be configuring project on my running server. I’ll provide my server access details for configuration project. I also need documentation for configure on server.