Ajax - networkstatus "pending"

Ik probeer via ajax een drodown met landen en provincies te vullen dat gaat soms goed(en snel) en soms blijft hij pending en dat kan 15 min of oneindig duren:

	$(document).on("change", ".regions", function(e) {
	$(".loading-div").show();
	pp = $("#reg1").val();
	r = $(this).attr("data-field"), o = $(this).val(), iso = $("option:selected", this).attr("iso"), "region1" == r && "region2" != r ? ($(".regions.district.adcatselect").html('<option value="" selected="SELECTED"><?=$_SESSION['def']['CHOOSE_CITY']?></option>'),  $.ajax({
	type: "POST",
	url: "<?=HTML_ROOT?>inc/region2select.php?time=<?=time()?>",
	data: {
		region1Url: o
	},
	dataType: "html",
	encode: !0
	}).done(function(t) {
	// laad iso
	$("#iso").val(iso);	
	$(".loading-div").hide(), $(".regions.city").html(t)
	})) : "region2" == r && "region1" != r ? ($(".regions.district.adcatselect").val(null),  $.ajax({
	type: "POST",
	url: "<?=HTML_ROOT?>inc/region3select.php?time=<?=time()?>",
	data: {
		region2Url: "" + o,region1Url:pp
	},
	dataType: "html",
	encode: !0
	}).done(function(t) {
		
	$(".regions.district").html(t),$(".loading-div").show(), $.ajax({
		type: "POST",
		url: "<?=HTML_ROOT?>inc/latlngselect.php?time=<?=time()?>",
		data: {
			region2Url: "" + o,region1Url:pp
		},
		dataType: "json",
		encode: !0
	}).done(function(t) {
	//alert(t);
		ca = t.split(' ');
		
		$(".loading-div").hide(),$("#lat").val(ca[1]), $("#lng").val(ca[0])
	}), $(".loading-div").hide()
	})) : "region3" == r && $.ajax({ // lnglat van reg3
	type: "POST",
	url: "<?=HTML_ROOT?>inc/latlngselect.php",
	data: {
		region3Url: o,
		region1Url:pp,
		region2Url: $(".regions.city").val()
	},
	dataType: "json",
	encode: !0
	}).done(function(rt) {
		//alert(rt);
		caa = rt.split(' ');
		
		$(".loading-div").hide(),$("#lat").val(caa[1]), $("#lng").val(caa[0])
	});
	})

Deze loopt hij meestal op vast:

url: "<?=HTML_ROOT?>inc/region3select.php?time=<?=time()?>",

Dus het is de ene call na de andere.
Hoe kan ik dit soepel laten verlopen?