dynamically subscribe items

[rd2008]

yes it works

[rd2008]

any way, in this method is there any way to get the list of all the subscribed items initially.
or at least the number of items that is subscribed to that user?

To create the table correctly, i need the number of subscribed items in the web client. is it possible to catch it in the onStart() method in js or in some other method. Also can you please elaborate the use of setSnapshotRequried(true) onEngineCreation. I think i may use it. can you please elaborate?

[DarioCrivelli]

This metainformation is not supplied, though your suggestion about onStart makes sense.
At the moment, you would need to setup a separate item to get this information.
The group names were introduced as shortcuts for known sets of items, like stock lists.
Note that, for unknown sets, the COMMAND mode is also available, though it covers the more generic case of dynamic sets and requires specific handling by the Data Adapter.

By issuing setSnapshotRequired(true), you ask for a preliminary update about the current state of the item (for each item in the table). The Server tries to send this update immediately.
The snapshot is covered in the "DOCS-SDKs/General Concepts.pdf" document, paragraph 3.4.1.

onEngineCreation allows you to perform Engine initialization (The Engine page connects to Lightstreamer Server on behalf of one or more Push-Pages). The Master Push-page, after creating the Engine through "createEngine", receives a call to the onEngineCreation callback, through which it can (and should) configure the Engine so that it can access the Server.
Details can be found in the online documentation, but the normal usage is best described by the provided sample pages.