CPSC415A
Web Programming

Request Animation Frame

var DURATION = 1000
var startTime = null;

var step = function(currentTime) {
    if (startTime == null) {
        startTime = currentTime;
    }
    var fraction = (currentTime - startTime) / DURATION;
    var theDiv = document.getElementById('theDiv');
    theDiv.style.opacity = interp(0, 1, fraction) + '';
    if (fraction < 1.0) {
        window.requestAnimationFrame(step);
    }
}