var lis = document.getElementsByTagName("li");

for (var i = 0; i < lis.length; i++) {
  console.log(lis[i]);
}

//JavaScript
window.onbeforeunload = function (e) {
    document.getElementById("text").id = "active";
    var spans = document.getElementsByTagName('span');
    for (var i = 0;i < spans.length;i ++){
       (spans\[i\]).id = "active";
    }
}

/* CSS */
span {
    position: relative;
    animation-name: startloadingspan;
    animation-duration: 0.8s;
}

@keyframes startloadingspan {
    0% {
        opacity: 0;
    }
    100% {
        opacity: 1;
    }
}

span#active {
    position: relative;
    animation-name: endloadingspan;
    animation-duration: 0.8s
    animation-fill-mode: forwards;
}

@keyframes endloadingspan {
    0% {
        opacity: 1;
    }
    100% {
        opacity: 0;
    }
}