whenever the user has to choose among a set of elements the entire set is
packed in a suitable HTML input element (e.g.,
SELECT) and sent to the browser.
This approach, however, makes it impossible to edit large databases. ERW aims at the greatest generality, and thus implements on top of HTTP a simulated remote procedure call (RPC) mechanism using a hidden frame (this technique is often called remote scripting).
Every form contains an invisible
IFRAME element that is used to interact with the
server. Whenever the user interface code needs some data from the
database (for instance, because the user is browsing a set of entities)
the location of the
IFRAME element is
set to a particular URL that will load into the
manipulates via the DOM the user interface, shows these data to the