diff --git a/qutebrowser/browser/webengine/webenginetab.py b/qutebrowser/browser/webengine/webenginetab.py
index 81da3fb28..27183b765 100644
--- a/qutebrowser/browser/webengine/webenginetab.py
+++ b/qutebrowser/browser/webengine/webenginetab.py
@@ -230,9 +230,16 @@ class WebEngineScroller(browsertab.AbstractScroller):
                 # shutting down a tab
                 return
             assert isinstance(jsret, dict), jsret
-            self._pos_perc = (jsret['perc']['x'], jsret['perc']['y'])
             self._pos_px = QPoint(jsret['px']['x'], jsret['px']['y'])
-            self._at_bottom = jsret['at_bottom']
+
+            dx = jsret['scroll']['width'] - jsret['inner']['width']
+            perc_x = 0 if dx == 0 else 100 / dx * jsret['px']['x']
+            dy = jsret['scroll']['height'] - jsret['inner']['height']
+            perc_y = 0 if dy == 0 else 100 / dy * jsret['px']['y']
+
+            self._at_bottom = dy == jsret['scroll']['height']
+            self._pos_perc = perc_x, perc_y
+
             self.perc_changed.emit(*self._pos_perc)
 
         js_code = javascript.assemble('scroll', 'pos')
diff --git a/qutebrowser/javascript/scroll.js b/qutebrowser/javascript/scroll.js
index 69e8adf9c..fa0f311b3 100644
--- a/qutebrowser/javascript/scroll.js
+++ b/qutebrowser/javascript/scroll.js
@@ -61,26 +61,17 @@ window._qutebrowser.scroll = (function() {
 
     funcs.pos = function() {
         var elem = document.documentElement;
-        var dx = elem.scrollWidth - window.innerWidth;
-        var dy = elem.scrollHeight - window.innerHeight;
-        var perc_x, perc_y;
-
-        if (dx === 0) {
-            perc_x = 0;
-        } else {
-            perc_x = 100 / dx * window.scrollX;
-        }
-
-        if (dy === 0) {
-            perc_y = 0;
-        } else {
-            perc_y = 100 / dy * window.scrollY;
-        }
 
         var pos = {
-            "perc": {"x": perc_x, "y": perc_y},
             "px": {"x": window.scrollX, "y": window.scrollY},
-            "at_bottom": dy === window.scrollY,
+            "scroll": {
+                "width": elem.scrollWidth,
+                "height": elem.scrollHeight,
+            },
+            "inner": {
+                "width": window.innerWidth,
+                "height": window.innerHeight,
+            },
         };
 
         // console.log(JSON.stringify(pos));