Can anyone help me figure out how to do this Javascript? -

i saw website http://www.montere.it/?lang=en , love how use javascript on website. when scroll down, image appear , flip. have tried hard find sample online none of them this. or @ least can give me website has javascript collection.

appreciate help.

i ripped css animation code straight out of page

@keyframes flipiny {     0% {         -webkit-transform:perspective(1000px) rotatey(20deg);         -ms-transform:perspective(1000px) rotatey(20deg);         transform:perspective(1000px) rotatey(20deg);         opacity:0     }     100% {         -webkit-transform:perspective(1000px) rotatey(0deg);         -ms-transform:perspective(1000px) rotatey(0deg);         transform:perspective(1000px) rotatey(0deg);         opacity:1     } } .flipiny {     -webkit-backface-visibility:visible !important;     -ms-backface-visibility:visible !important;     backface-visibility:visible !important;     -webkit-animation-name:flipiny;     animation-name:flipiny } .animated {     -webkit-animation-duration:.7s;     animation-duration:.7s;     -webkit-animation-fill-mode:both;     animation-fill-mode:both } 

run jsfiddle http://jsfiddle.net/4of7l5al/4/

basically when user scrolls, add animated class element.