add hotkeys to scroll headlines/articles (whichever is active) by one page

include/functions.php

@@ -1121,6 +1121,8 @@
 			"*(40)|Shift+Down" => "article_scroll_down",
 			"^(38)|Ctrl+Up" => "prev_article_noscroll",
 			"^(40)|Ctrl+Down" => "next_article_noscroll",
+			"(33)|Page Up" => "article_page_up",
+			"(34)|Page Down" => "article_page_down",
 			"/" => "search_dialog",
 			"s" => "toggle_mark",
 			"S" => "toggle_publ",

js/Article.js

@@ -314,6 +314,20 @@ define(["dojo/_base/declare"], function (declare) {
 			else
 				return 0;
 		},
+		scrollPages: function (offset) {
+			if (!App.isCombinedMode()) {
+				const ci = $("content-insert");
+				if (ci) {
+					ci.scrollTop += ci.offsetHeight * offset * 0.9;
+				}
+			} else {
+				const hi = $("headlines-frame");
+				if (hi) {
+					hi.scrollTop += hi.offsetHeight * offset * 0.9;
+				}
+
+			}
+		},
 		scroll: function (offset) {
 			if (!App.isCombinedMode()) {
 				const ci = $("content-insert");

js/tt-rss.js

@@ -204,8 +204,8 @@ require(["dojo/_base/kernel",
 					if (event.target.nodeName == "INPUT" || event.target.nodeName == "TEXTAREA") return;
 
 					// Arrow buttons and escape are not reported via keypress, handle them via keydown.
-					// escape = 27, left = 37, up = 38, right = 39, down = 40
-					if (event.type == "keydown" && event.which != 27 && (event.which < 37 || event.which > 40)) return;
+					// escape = 27, left = 37, up = 38, right = 39, down = 40, pgup = 33, pgdn = 34
+					if (event.type == "keydown" && event.which != 27 && (event.which < 33 || event.which > 40)) return;
 
 					const action_name = App.keyeventToAction(event);
 
@@ -330,6 +330,12 @@ require(["dojo/_base/kernel",
 					this.hotkey_actions["article_scroll_up"] = function () {
 						Article.scroll(-40);
 					};
+					this.hotkey_actions["article_page_down"] = function () {
+						Article.scrollPages(1);
+					};
+					this.hotkey_actions["article_page_up"] = function () {
+						Article.scrollPages(-1);
+					};
 					this.hotkey_actions["close_article"] = function () {
 						if (App.isCombinedMode()) {
 							Article.cdmUnsetActive();