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[Mike Dierken]

> > For example, which (if any) of the following two FORMs is 'safe':
> > 
> > <form method='GET' action='../cgi-bin/nifty.cgi'>  <input 
> > type='submit' value='go' /> </form>
> > 
> > <form method='POST' action='../cgi-bin/nifty.cgi'>  <input 
> > type='submit' value='go' /> </form>
> > 
> 
> I don't see anything particularly unsafe about either of them, but I
> think I can see what you're getting at.
> 
> Perhaps "without side-effects" or "idempotent" might be better
> descriptions than "safe"? The above two forms both look like they're
> doing exactly what they were intended to do, and therefore don't seem
> "unsafe" at all...

I'm pretty sure I'm doing a very poor job communicating what I'm thinking...
So thanks for sticking with this. 

Each of the HTTP methods GET, PUT and DELETE are idempotent (repeating them
results in the same state).
Only GET is safe (no data is intended by the client to be modified).