使用javascript而不是jQuery的简单ajax表单

I'm working with a form for which the mark-up I can't change & can't use jQuery. Currently the form post the results to a new window. Is it possible to change this to an ajax form so that the results displays on submit instead without altering any mark-up? Pulling the results (mark-up) from the results page back to the form page.I'm working with a form for which the mark-up I