Dreamweaver CS6: The Missing Manual

Comparing Versions of a Web Page

Sometimes you make a change to a page, save it, preview it, close it, and move along to the next assignment for the day. Only later, when you take a second look at your day’s changes before moving pages to your web server, do you see that one of them has a problem you didn’t notice at first. Perhaps the left sidebar is suddenly wider than it was before. Since you already closed the file, you can’t use the Undo command to reverse whatever pesky mistake you made. You could, of course, retrieve the current version of the page from the server, thus overwriting your changes. But what if you did a lot of good work on the page—added text, graphics, and links—that you don’t want to lose? Ideally, you’d like to see all the changes you made to the page, and selectively undo the mistake you accidentally introduced.

Enter the Compare File command. With it, you can compare two files and identify lines of code that differ between them. This tool is a perfect solution for problems like the unintentionally botched sidebar above. Compare the local file (the one with the messed-up sidebar) with the remote file (the live version of the website page that works, but is missing your most recent edits). You can then identify any changes you made and smoke out your mistake.

Dreamweaver doesn’t actually have this tool built into it. Instead, it just passes the files to a separate file-comparison utility (often called a “diff” tool, since it identifies differences between files). ...