diff --git a/src/api.js b/src/api.js
index 3d97f53c9..cccd4b152 100644
--- a/src/api.js
+++ b/src/api.js
@@ -19,7 +19,7 @@
       return this.page.view;
     },
     getViewport: function(scale, rotate) {
-      if (arguments < 2)
+      if (arguments.length < 2)
         rotate = this.rotate;
       return new PDFJS.PageViewport(this.view, scale, rotate, 0, 0);
     },
diff --git a/web/viewer.js b/web/viewer.js
index 9fe9a1714..3c7279fb4 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -747,8 +747,6 @@ var PageView = function pageView(container, pdfPage, id, scale,
     var viewport = this.pdfPage.getViewport(this.scale);
 
     this.viewport = viewport;
-    this.width = viewport.width;
-    this.height = viewport.height;
     div.style.width = viewport.width + 'px';
     div.style.height = viewport.height + 'px';
 
@@ -763,6 +761,20 @@ var PageView = function pageView(container, pdfPage, id, scale,
     div.appendChild(this.loadingIconDiv);
   };
 
+  Object.defineProperty(this, 'width', {
+    get: function PageView_getWidth() {
+      return this.viewport.width;
+    },
+    enumerable: true
+  });
+
+  Object.defineProperty(this, 'height', {
+    get: function PageView_getHeight() {
+      return this.viewport.height;
+    },
+    enumerable: true
+  });
+
   function setupAnnotations(pdfPage, viewport) {
     function bindLink(link, dest) {
       link.href = PDFView.getDestinationHash(dest);