closes #2878

public/src/client/category.js

@@ -89,8 +89,8 @@ define('forum/category', [
 		});
 	};
 
-	Category.navigatorCallback = function(element, elementCount) {
+	Category.navigatorCallback = function(topIndex, bottomIndex, elementCount) {
-		return parseInt(element.attr('data-index'), 10) + 1;
+		return bottomIndex;
 	};
 
 	$(window).on('action:popstate', function(ev, data) {

public/src/client/topic.js

@@ -148,18 +148,18 @@ define('forum/topic', [
 		return index;
 	};
 
-	Topic.navigatorCallback = function(element, elementCount) {
+	Topic.navigatorCallback = function(topPostIndex, bottomPostIndex, elementCount) {
 		var path = ajaxify.removeRelativePath(window.location.pathname.slice(1));
 		if (!path.startsWith('topic')) {
 			return 1;
 		}
-		var postIndex = parseInt(element.attr('data-index'), 10);
+		var postIndex = topPostIndex;
-		var index = postIndex + 1;
+		var index = bottomPostIndex;
 		if (config.topicPostSort !== 'oldest_to_newest') {
-			if (postIndex === 0) {
+			if (bottomPostIndex === 0) {
 				index = 1;
 			} else  {
-				index = Math.max(elementCount - postIndex + 1, 1);
+				index = Math.max(elementCount - bottomPostIndex + 2, 1);
 			}
 		}
 
@@ -175,8 +175,8 @@ define('forum/topic', [
 			var topicId = parts[1],
 				slug = parts[2];
 			var newUrl = 'topic/' + topicId + '/' + (slug ? slug : '');
-			if (postIndex > 0) {
+			if (postIndex > 1) {
-				newUrl += '/' + (postIndex + 1);
+				newUrl += '/' + postIndex;
 			}
 
 			if (newUrl !== currentUrl) {

public/src/modules/navigator.js

@@ -90,18 +90,26 @@ define('navigator', ['forum/pagination'], function(pagination) {
 	navigator.update = function() {
 		toggle(!!count);
 
-		$($(navigator.selector).get().reverse()).each(function() {
+		var topIndex = 0;
+		var bottomIndex = 0;
+		$(navigator.selector).each(function() {
 			var el = $(this);
 
 			if (elementInView(el)) {
-				if (typeof navigator.callback === 'function') {
+				if (!topIndex) {
-					index = navigator.callback(el, count);
+					topIndex = parseInt(el.attr('data-index'), 10) + 1;
-					navigator.updateTextAndProgressBar();
+				} else {
+					bottomIndex = parseInt(el.attr('data-index'), 10) + 1;
 				}
-
+			} else if (topIndex && bottomIndex) {
 				return false;
 			}
 		});
+
+		if (typeof navigator.callback === 'function' && topIndex && bottomIndex) {
+			index = navigator.callback(topIndex, bottomIndex, count);
+			navigator.updateTextAndProgressBar();
+		}
 	};
 
 	navigator.updateTextAndProgressBar = function() {

public/src/modules/share.js

@@ -50,7 +50,7 @@ define('share', function() {
 
 	function getPostUrl(clickedElement) {
 		var parts = window.location.pathname.split('/');
-		var postIndex = parseInt(clickedElement.parents('data-index').attr('data-index'), 10);
+		var postIndex = parseInt(clickedElement.parents('[data-index]').attr('data-index'), 10);
 		return '/' + parts[1] + '/' + parts[2] + (parts[3] ? '/' + parts[3] : '') + (postIndex ? '/' + (postIndex + 1) : '');
 	}