diff --git a/static/js/URL.js b/static/js/URL.js
index 1e4f7422..d5eac2da 100644
--- a/static/js/URL.js
+++ b/static/js/URL.js
@@ -143,7 +143,7 @@ pandora.URL = (function() {
                     set['part.' + state.page] = state.part;
                 }
                 if (state.span) {
-                    set['documents.' + state.part + '.position'] = state.span;
+                    set['documents.' + state.part] = {position: state.span};
                 }
                 pandora.UI.set(set);
                 callback && callback();