Get body content and put it into a description text box on a new page using JQuery

Get body content and put it into a description text box on a new page
using JQuery

So I have a discussion list(like a forum page) and I have a button on this
page that links me to a create a project form. What I want to do is when I
click on that button and it opens the form how do I pull the body content
from that page (will be the OP post) and then drop it in the description
box on the form using JQuery.
Doing this to bypass copying the content clicking the button and then
pasting in description. Even if I can figure out how to identify that body
content for now. So like a script that gets that content and an alert runs
showing me the content.
Thanks