First go to any page from you want to copy (download) text .
Open a new tab
Go to the next address. (You may save it as a bookmark)
Paste the copied address in the textbox.
Press button "Convertir archivo" (this page is in spanish)
Select a folder to download the file
Download is done
Locate the downloaded file and decompress it wih WinZip, WinRar or similar
Open the file with your favorite browser like Firefox, it is an .html file
Select text and copy
Paste in a document