Okay....... a working version at last.
There are still display issues, but the major problems were cleared up after the tip by rnd me, that led me to discover the need for inline styles.
Immediate display problems relate to:
Establishing the workspace height for any screen/browser
I finally went with pixels, just to get the system working, but by zooming out, the workspace is wasted.
There are I'm sure, ways around this....... It does look a little noobish, by failing to provide scalable height.
Line spacing - Pasted web site text is more difficult to read
When typing text, one would automatically hit enter twice to insert 2 linebreaks (as per this post for paragraphs).
Therefore typed text is perfect(?)
When pasting a web page contents, typically only one linebreak is used, because in HTML, the additional spacing is automatically provided.
I don't see any way around this other than by human intervention.
Save to a text file, and literally add line breaks for clarity, and then use for translation.
I've yet to test the prog on anything other than Chrome & Firefox.
Both will be very up to date cos I run Ubuntu 12.04.
There are sure to be issues with IE and older kit, but we'll see.
You may well discover a few gaping holes in it (but that's good).
Anyway, here it is:
(read thru the short instructions first, to learn the best way forward)
Also a minor problem with the Google inserted header.
It is cut off at bottom.
zoom out zoom in and the problem disappears.