jQuery post function

If you use jQuery to post data, what is the accepted best practice for
passing parameters - by putting a query string in the url, or passing
them through the data argument of the function?

e.g.

$.post(/tasks/3?completed=true;,{ _method: “PUT” },null, “script”)

OR

$.post(/tasks/3;,{ _method: “PUT”,completed: true },null, “script”)

cheers,

DAZ