You need to be more specific with your question. Technically speaking, a form INPUTS data, it doesn't output anything. The form posts data to a PHP page (script) that processes the form data and will usually output something.
Can I assume that the X and Y values are being outputted on the page that follows the form? Or are these two values showing up INSIDE the form itself? (If so, that might be some Javascript code that's intermingled with the form).
If they are showing up on the following page, then you need to look at the part of the code that Prints / Displays / Outputs. It might be showing sessionID's, cookie values, database information or something else like that to help you troubleshoot problems. If you don't want them in the output, then you edit the script so that it doesn't display those values anymore. (Comment out print statements that show values that you don't need displayed).
It's very possible that the X and Y values are important to the script so don't simply delete any references to them. But if the script is outputting something that you don't need displayed, it's OK to comment out the lines that display those values.
