I have some data, lets say:
var dat = JSON.stringify(frm.serializeArray())
I want to submit this to the server using a roundtrip (aka, non
You would need to assign the json string to an input's value inside a form tag in order for it to get POSTed to the server (either by the user submitting the form or by clicking the submit button programmatically).
Alternatively from javascript you could use window.location to send the variable as part of a GET request.