I think what you may be looking for is web methods, it allows the jquery (client side) to call the backend (c#) and for them to interact with each other.
Check out this link for reference:
http://encosia.com/using-jquery-to-directly-call-aspnet-ajax-page-methods/
Here is a brief summary from the website:
When it comes to lightweight client-side communication, I’ve noticed
that many of you prefer ASP.NET AJAX’s page methods to full ASMX web
services. In fact, page methods came up in the very first comment on
my article about using jQuery to consume ASMX web services. Given
their popularity, I’d like to give them their due attention. As a
result of Justin‘s question in those comments, I discovered that you
can call page methods via jQuery. In fact, it turns out that you can
even do it without involving the ScriptManager at all. In this post, I
will clarify exactly what is and isn’t necessary in order to use page
methods. Then, I’ll show you how to use jQuery to call a page method
without using the ScriptManager.