If you edit a file locally and then try to upload it to your remote server, Dreamweaver will notify you if the remote version of the file has changed. Dreamweaver gives you the option of comparing the two files before you upload the file and overwrite the remote version.
Before you start, you must install a file comparison tool on your system and specify it in Dreamweaver. For more information, see Specifying a comparison tool in Dreamweaver.
If the remote version of the file has been modified, Dreamweaver notifies you and gives you the option of seeing the differences.
The file comparison tool starts and compares the two files.
If you havent specified a file comparison tool, Dreamweaver prompts you to specify one.