diff --git a/src/support.js b/src/support.js
index 9a6a318d1..9ffad2803 100644
--- a/src/support.js
+++ b/src/support.js
@@ -206,7 +206,7 @@ jQuery.support = (function() {
 		marginDiv.style.marginRight = "0";
 		div.appendChild( marginDiv );
 		support.reliableMarginRight =
-			( parseInt( document.defaultView.getComputedStyle( marginDiv, null ).marginRight, 10 ) || 0 ) === 0;
+			( parseInt( ( document.defaultView.getComputedStyle( marginDiv, null ) || { marginRight: 0 } ).marginRight, 10 ) || 0 ) === 0;
 	}
 
 	// Remove the body element we added