diff --git a/styles/prosilver/template/portal/modules/portal_clock.js b/styles/prosilver/template/portal/modules/portal_clock.js
index 7ca0b85d..2bc60d82 100644
--- a/styles/prosilver/template/portal/modules/portal_clock.js
+++ b/styles/prosilver/template/portal/modules/portal_clock.js
@@ -20,9 +20,16 @@ phpbb.b3pFlipClock = function(identifierUp, identifierDown, val, type) {
 	var backIdUp = identifierUp.replace('-front-', '-back-');
 	var backIdDown = identifierDown.replace('-front-', '-back-');
 	var backPosition = $(backIdUp).css('background-position');
-	var backPositionLength = backPosition.length;
+	var backPositionLength;
 	var backY;
 
+	// Workaround for Internet Explorer bug
+	if (backPosition === undefined) {
+		backPosition = $(backIdUp).css('background-position-x') + ' ' + $(backIdUp).css('background-position-y');
+	}
+
+	backPositionLength = backPosition.length;
+
 	if (backPosition.substring(backPositionLength - 3, backPositionLength - 2) === '0') {
 		backY = '0px';
 	} else {
@@ -59,6 +66,12 @@ phpbb.b3pFlipClock = function(identifierUp, identifierDown, val, type) {
 
 	// now get the vertical offset of the bottom digit
 	backPosition = $(identifierDown).css('background-position');
+
+	// Workaround for Internet Explorer bug
+	if (backPosition === undefined) {
+		backPosition = $(backIdUp).css('background-position-x') + ' ' + $(backIdUp).css('background-position-y');
+	}
+
 	backPositionLength = backPosition.length;
 
 	if (backPosition.substring(backPositionLength - 3, backPositionLength - 2) === '0') {