VisualViewport

var bottomBar = document.getElementById("bottombar");
var viewport = window.visualViewport;

function resizeHandler() {
  if (viewport.scale > 1.3) bottomBar.style.display = "none";
  else bottomBar.style.display = "block";
}

window.visualViewport.addEventListener("resize", resizeHandler);

var bottomBar = document.getElementById("bottombar");
var viewport = window.visualViewport;
function viewportHandler() {
  var layoutViewport = document.getElementById("layoutViewport");

  // Since the bar is position: fixed we need to offset it by the visual
  // viewport's offset from the layout viewport origin.
  var offsetLeft = viewport.offsetLeft;
  var offsetTop =
    viewport.height -
    layoutViewport.getBoundingClientRect().height +
    viewport.offsetTop;

  // You could also do this by setting style.left and style.top if you
  // use width: 100% instead.
  bottomBar.style.transform =
    "translate(" +
    offsetLeft +
    "px," +
    offsetTop +
    "px) " +
    "scale(" +
    1 / viewport.scale +
    ")";
}
window.visualViewport.addEventListener("scroll", viewportHandler);
window.visualViewport.addEventListener("resize", viewportHandler);