can anyone here tell me a little thing about orca?

hello...

i know that orca is 100% ajax, but i still want to know the trick of this software that make browser's "back and forward button"  work perfectly.

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what i know is , if we use ajax, the browser's back and forward button doesn't work.

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i think there must be a hidden iframe to make this trick..

this ganna be better if i search my self