@dsonesuk
I've found multiple troubles in a lot of pages. Similar examples works and others not...
https://www.w3schools.com/cssref/playit.asp?filename=playcss_filter&preval=blur(5px) Works.
Everything under More Examples, not.
True, I use chrome 49 and have need 53, but why they did not put everything?
I've found another strange situation, nut I do not remember where was. Or I've found examples that not should work on my browser and instead go well...
Same on Font Weight; It works partially. Numbers are 9 but work as are 2.
https://www.w3schools.com/cssref/pr_font_weight.asp