@sgunhouse hum, thanks for the info, still odd since i have adguard plugin for block ads and also the build in blocker of opera, so usually i dont see and neither click ads,
but i can even warantee it in this case since i was looking for "ambigrams" and i openes several urls at same time from google, with the wheel button, meaning the 3 or 4 websites i did open were not even active view tabs, and then when i made them active to wich was the one i wanted, boom, i saw the opera landing page and JS file download.
maybe those ads are using a bug from some websites that allow them to load inside the legit URL website, because the downloaded JS file came from the legit URL too. Thats my guess, i dont know,
I even wrote a mail to the guy of the website, but got no response
thanks for your reply