是否可以在HTML5或css中循环更改不透明度值?

This is the code I'm currently working with. It works to my purposes of layering the two images. What I am trying to do is have the layer0 opacity lower to 0 as the layer1 opacity increases to 100 over a few seconds. {and then on to layer1 with layer2 and so on eventually looping back to layer0}This is the code I'm currently working with. It