Submit form with Ajax

Hi,

Is it possible to submit a form using Ajax? If yes would somebody have a working example?

In particular I am looking at what to use in the "url" and "data" parameters.

$.ajax({
      type: "POST",
      url: ???,
      data: ???,
      success: function(msg) {
          alert("Success");
       }
});

I need one field of my form to be updated in the database on a button click and on success do some additional processing.