Firefox transitions not working
This is my CSS setup: #element1, #element2{ -webkit-transition: left 0.3s; -moz-transition: left 0.3s; -o-transition: left 0.3s; transition: left 0.3s; } body.open #element1, body.open #element2 { left: 245px; } The problem is that the transition just doesn't work in Firefox, it's fine in all other browsers. 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