JQuery :: Ajax Process A Textarea?

I have a form with a textarea that can hold a lot of values. When submitted, a php-script takes over and processes the textarea line by line. When a lot of values is submitted, it can be time-consuming for the php-script, causing the webserver to timeout.

I would like jquery/ajax to send one or a few lines of the textarea to the php-script at a time, hence feeding the php-script with a lot of smaller requests instead of one massive one. Kind of like an upload form with a progress bar, but for textarea values instead of file submition.

I have looked around and failed to find any examples or tutorials on this, and since I'm not very experienced in javascript I would really need it.

So again, the javascript would check the textarea-field when user submits the form, and send one or five values from the field at a time to a remote php-script. In the meantime the user can be presented with a "loading..."-image or a progress bar.