let ias = new InfiniteAjaxScroll(/*..*/, {
// element to show as spinner
// this is the minimal time the loader should be displayed. If loading takes longer, the spinner
// will be shown for the duration of the loading. If the loading takes less then this duration,
// say 300ms, then the spinner is still shown for 600ms.
// this function is called when the button has to be shown
show: function(element) {
element.style.opacity = '1'; // default behaviour
// this function is called when the button has to be hidden
hide: function(element) {
element.style.opacity = '0'; // default behaviour