Greasy Fork is available in English.
HTML5 player for AtresPlayer.com, avoiding the Flash Player plugin and sundry advertisements. Adds a download button.
I managed to download subtitles for all series except 7 on Firefox with GreaseMonkey on it.
And first message is for Opera with ViolentMonkey.
BTW your page https://swyterzone.appspot.com is off due to "Support for Python 2.5 has turned off. Please refer to https://goo.gl/aESk5L for more information"
It doesn't work for all series
For example:
http://www.atresplayer.com/television/series/alli-abajo/temporada-3/capitulo-10-captulo-embarazo-mltiple_2017051900557.html
I can confirm for Alli Abajo it works only for series 13,12,11,8,6,4 but not for others.
Can you check it out?