diff --git a/src/CheckSessionIFrame.js b/src/CheckSessionIFrame.js
index 17d83043..3da0aa05 100644
--- a/src/CheckSessionIFrame.js
+++ b/src/CheckSessionIFrame.js
@@ -22,8 +22,8 @@ export class CheckSessionIFrame {
         this._frame.style.visibility = "hidden";
         this._frame.style.position = "absolute";
         this._frame.style.display = "none";
-        this._frame.style.width = 0;
-        this._frame.style.height = 0;
+        this._frame.width = 0;
+        this._frame.height = 0;
 
         this._frame.src = url;
     }
diff --git a/src/IFrameWindow.js b/src/IFrameWindow.js
index 1bbcfed1..fdc2ea48 100644
--- a/src/IFrameWindow.js
+++ b/src/IFrameWindow.js
@@ -21,8 +21,8 @@ export class IFrameWindow {
         // shotgun approach
         this._frame.style.visibility = "hidden";
         this._frame.style.position = "absolute";
-        this._frame.style.width = 0;
-        this._frame.style.height = 0;
+        this._frame.width = 0;
+        this._frame.height = 0;
 
         window.document.body.appendChild(this._frame);
     }