how to dynamically append data to form post without ajax OR input tags

Question

I am analyzing header tags for submitting forms online in order to better understand how htmlhttp forms work- signing in to gmail, yahoo mail, and amazon, using the network tab of google developer tools, to view the http headers of requests and responses, and learn where they come from. I am seeing very peculiar behavior in my browser's (chrome)request headers when signing into amazon. The form data, always has the following two header names appended to the second and third to last places of the form data query: x=(some random number), and y=(some random number).

There are no input tags getting dynamically generated, since when i step through the code using breakpoints, none ever get added, and when i tell google chrome to break on all subtree modifications, the site still sends off the post with the added parameters before anything gets modified.

There also is NO ajax call which is causing dynamically added data to be appended to the form post, since google developer tools shows no ajax comes before the form post in the timeline of the network tab.

My question is this: is there any way, using javascript, to instruct a browser, to append data to a form post, WITHOUT the use of dynamically appended input elements, or ajax?

Answer 1

If you are talking about the x & y variables specifically, then it came from an <input type="image"> . You could try playing with input type image and see how it behaves.

But for other cases (where you want to add any other variable) then I think the best way is to append input elements on the fly.