I think Slashdot places a unique ID on the *form* page and tacks this onto the actual posted comment. If it detects the same ID is already in use (or perhaps the same ID with the same subject/title), it can infer that the user clicked Submit twice or hit Reload, and can ignore the 2nd post.

The drawback, of course, is that I can't type up a comment, submit it, go back and type up a new/2nd comment, because the "ID" in the form will already be added to the system due to my previous comment. I'd have to refresh the page that has the form so as to get a new ID.

In reply to RE: Don't allow duplicate posts with the same title by Fastolfe
in thread Don't allow duplicate posts with the same title by princepawn

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