ASP.NET asynchronous post-back on asp:button click

I am using AJAX in asp:net and am trying to handle a situation where an asp:button triggers both a javascript method and a codebehind c# method. To do this I am using onclick and onClientClick attributes for the button. I need a postback to occur for the codebehind to be called however this postback causes the javascript to not work because variables have lost state. Can anyone describe how to handle this? Possible with ajax and async postbacks? It’s starting to drive me a bit crazy!

How to parameterise table name in ODBC query

I have an ODBC connection to a database and I would like the user to be able to view data within any table. As this is an ASP.net application I cannot trust that the table name sent doesn’t also contain nasties. I have tried using a parameterised query but I always get an error saying that I “Must declare the table variable” – this appears to be an issue because it is the table name