<html>
<style>
#janktest{
  width: 1000px;
  height: 10000px;
}
</style>
<body onload='setup()'>
 <div id="janktest"></div>
</body>
<script>
function setup() {
  document.getElementById('janktest').addEventListener('touchstart', (e) => {
    var end = performance.now() + 1200;
    while (performance.now() < end);
  }, {passive: false});
}
</script>
</html>