Difference between Postback and ISpostback?

-:Difference between Postback and ISpostback? :-

There are some definition of postback.
Post back is the process the sending data get back to server
for processing.

Is post back property checks whether page is being loaded for
first time.
if it is False :means first time loaded.
if it is True: means round trip to server.
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Postback: Postback is a event which fire when page data goes to server.

IsPostBack: Ispostback is page property of bool type and it become true when page come again to browser.
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PostBack: Postback is the event which sends the form data
to the server. The server processes the data & sends it
back to the browser. .

And the IsPostBack property of
the page object may be used to check whether the page
request is a postback or not.

IsPostBack property is of the
type Boolean.