How would you like to receive information on a new page (the old one, which is replaced by new content, this is a new page), ajax is not the answer, because it is used to place new content on the old page.
I would recommend injecting the form into the current page using javascript and submitting the form programmatically.
Quick'n'dirty (untested):
$("#formsPlaceholder").append('<form action="newpage" method="post" id="newForm"><input type="textfield" name="foo" value="bar"/></form>');
$("#newForm").submit();