It looks like you are trying to use a PHP variable in javascript. You can use .serialize to gather data and pass it to the ajax call. But as for making calls with different named variables for the name of the value pair, you will need to gather that information from the php page you are passing.
Example:
$.get("jQueryFunctions.php?action=checkCaptula",$('#resetPasswordDiv :input').serialize()).done(function(data){ ....
While this is a .get instead of a .ajax, it's just shorthand for the .ajax call. The passwordDiv contains HTML inputs with names and id. It gathers the information and passes it to the php page for processing.