<Select> widget with infinite scroll dropdown

Answer 1

I have provided a set of working example of combo-box using jQuery UI selectmenu. I have used basic JSON source for ajax request, please work on this part yourself.

$(".ajax-combo").selectmenu({
  "width": "100px",
});
$(".ajax-combo").selectmenu("menuWidget").addClass("make-scrolling");
$(".ajax-combo").selectmenu("menuWidget").scroll(function(e) {
  if (e.currentTarget.scrollHeight - 10 < e.currentTarget.scrollTop + $(e.currentTarget).height()) {
    var curTar = e.currentTarget;
    var lastTop = curTar.scrollTop;
    $.getJSON("http://echo.jsontest.com/10/test/20/rest/30/best/40/vest/50/fest", function(data) {
      $.each(data, function(key, val) {
        $(".ajax-combo").append("" + val + "");
      });
      $(".ajax-combo").selectmenu("refresh");
      curTar.scrollTop = lastTop;
    });
  }
});

.make-scrolling {
  overflow-y: scroll;
  height: 150px;
}