Why is css slider not working in firefox?

Question

css

There is a block, it is necessary that the background image of this block change smoothly to another, I found an article that describes the method in css.
I did everything as described in the article, the background changes perfectly, but it doesn’t want to work in ff, tell me what could be the problem?
My css

#slider{
width: 448px;
height: 251px;
margin: 0 auto;
background: url(1.jpg);
animation-name: slider;
animation-duration: 7s;
}

@keyframes slider{
0%{ background: url(1.jpg);}
33%{ background: url(2.jpg);}
66%{ background: url(3.jpg);}
}

I also set the -moz- prefix, it doesn’t fail, maybe there is some alternative way, for example, in js.

Answer 1

-webkit- ?

Answer 2

the fox can't animate background-image, here's my question one to one but not the slider