I read somewhere that css masks can be used in Firefox with svg files, but i can\'t make it work... Its working flawless in chrome and safari but i had no luck with firefox.
Was searching for css mask found this tutorial here, may help you. Showed a different method and it works fine with Mozilla
http://thenittygritty.co/css-masking
Example- http://www.der-schepp.de/css-masking/mouse.html
This is how you do it in Firefox. You apply SVG clipPaths and masks to html content. It's not the same syntax as webkit css masks but it can achieve the same effect.
There is this jquery pluggin, I end up choosing this solution, beacuse it is also cross-browser.
http://almogbaku.github.io/imageMask/
https://developer.mozilla.org/en-US/docs/CSS/mask
EDIT: As of Firefox 54 CSS masks should be supported according to http://caniuse.com/#feat=css-masks
It is not supported according to http://caniuse.com/#feat=css-masks