Calling functions from an ASP.NET code file with javascript

I have a JavaScript-based timeline which needs to use data from an SQL server. The queries and the JSON conversions have been worked out in the form of C#.NET functions within a code file related to an .aspx page.

So for a complete newbie to ASP.NET, how do you set up a function call like t开发者_StackOverflowhis from JavaScript?

I would love it if someone had some simple example code I could learn/get some pointers from.

Edit: I am using .NET 3.5

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This is how I do it with jQuery

$.getJSON("MyAction" { Data: somedata}, function(data) {
    // do stuff on callback
});