function isScrolledIntoView(el) {
var elemTop = el.getBoundingClientRect().top;
var elemBottom = el.getBoundingClientRect().bottom;
var isVisible = (elemTop >= 0) && (elemBottom <= window.innerHeight);
return isVisible;
}
$(window).scroll(function (event) {
$( ".view_box" ).each(function( index ) {
if (isScrolledIntoView(this)) {
$(this).parent().addClass('in_view');
}
});
});