Simple Greasemonkey Script

Need simple greasemonkey script. I have a webpage that has multiple textboxes in a table with content in it. The script must read the text in the textbox, then submit this content to a page on an external domain, that page will respond with some html. The html must be inserted into the table next to or below the textbox. Each page has between 1 a 30 textboxes. Each call to the external webpage takes 2-5 seconds. The calls must be done in the background, so the user can interact with the page as each element loads.