This is my CSS setup:
#element1, #element2{
-webkit-transition: left 0.3s;
-moz-transition: left 0.3s;
-o-transition: left 0.3s;
transition: left 0.3
You need to set a starting left for firefox (and now Chrome).
#element1, #element2{
left: 0px;
-webkit-transition: left 0.3s;
-moz-transition: left 0.3s;
-o-transition: left 0.3s;
transition: left 0.3s;
}
You're going to be better off always setting a default value for any transition. That way you can have complete control.