diff --git a/jquery/common.js b/jquery/common.js
index 0090d31..c891c0c 100644
--- a/jquery/common.js
+++ b/jquery/common.js
@@ -38,7 +38,8 @@ $.fn.setCursorPosition = function(pos)
 $.prototype.addButton = function(sType, sTitle, oClickLink, sId, sButtonClass, sTmpVar)
 {
 	$This = $(this);
-	var asAttributes = {id:(sId || ''), 'class':'button round'+(typeof sButtonClass != 'undefined'?' '+sButtonClass:'')};
+	sButtonClass = sButtonClass || '';
+	var asAttributes = {id:(sId || ''), 'class':'button round'+sButtonClass};
 	
 	//Link
 	var bLink = (typeof oClickLink == 'string');