What do we mean by postback? What is it good for?
In ASP, the predecessor of our ASP.NET version, transmitting and processing data was a lot more cumbersome. If a user entered data, the data had to be passed with POST or GET through one or more interim pages for validation and processing before it could be used. Of course, everytime the data is “touched”, errors can be introduced (think of the children’s game “Telephone”).
In ASP.NET, this has become much easier. Instead of running the controls on the client side, they are run right on the server. The server then posts the data back to itself for validation and processing - and that’s where the name comes from.
The postback function is a function that is automatically generated and included on our HTML page by the ASP.NET engine. In order for this to work correctly, the of the web page needs to include a server-side form that specifies the action to “runat” the “server”.