I have a small form inside a table. POSTing that form creates a new entity. I then want users to see that new entity, but it should open in a new window so that the original v
<form ... target="windowName">
or
<form ... target="windowName" onsubmit="window.open(this.action, this.target, '...attributes...');return true;">
...attributes... can consist of the stuff documented at the mozilla developer center or MSDN
One request, one response. That is the way of the web.
If you want a new window after a post, you either need to post the request from the new window in the first place- perhaps opened via javascript- or post your data from that page to the same page and save a token so that when the page re-loads is can open a new windows -again, likely with javascript- and that new window's request already knows about the previous post.