Описание тега dopostback
__doPostBack is a javascript method that allows to trigger a postback from the client.
The __doPostBack is a function which makes a postback to the server with an target element ID, and it should also fire the corresponding Event on server-side automatically.
It is used to fire events on the server side (server-side events are referred to as "actions" in EWF). It takes two arguments:
eventTarget - The name of the component (for example "cxWebButton1") that the event is being fired for.
eventArgument - The event identifier, for example 'CLICK' for the onClick event.