I am looking for something that is updating live and I think it should be done with javascript. But I just don't know what to look for or search for.
There are probably a lot of already coded stuff that I can grab out there and use for this little thing, but what is it called?

I have a page with a form on the left side with three empty fields that are supposed to be filled in and then inserted into a MySQL db.
On the right side there is an empty page, formatted by me with something like a header, a content area and a footer.
The first field on the left side is a headline, the second a text area and the third field a footer text.

When the user is writing text in the fields I would like the text to be updated live on the right side, so the user can see how the text looks like when it's being placed where it's supposed to be.

What should I look for? Is it javascript? Then what is this function called?
Or should I look for something else to make it work?

I am playing around in Dreamweaver (not sure if there is already something I can use there).