little performance improvement for getInheritedTheme

js/jquery.mobile.core.js

@@ -160,25 +160,24 @@ define( [ "jquery", "../external/requirejs/text!../version.txt", "./jquery.mobil
 			return nsNormalizeDict[ prop ] || ( nsNormalizeDict[ prop ] = $.camelCase( $.mobile.ns + prop ) );
 		},
 
+        // Find the closest parent with a theme class on it. Note that
+        // we are not using $.fn.closest() on purpose here because this
+        // method gets called quite a bit and we need it to be as fast
+        // as possible.
 		getInheritedTheme: function( el, defaultTheme ) {
-
-			// Find the closest parent with a theme class on it. Note that
-			// we are not using $.fn.closest() on purpose here because this
-			// method gets called quite a bit and we need it to be as fast
-			// as possible.
-
 			var e = el[ 0 ],
 				ltr = "",
 				re = /ui-(bar|body|overlay)-([a-z])\b/,
-				c, m;
+				m;
 
 			while ( e ) {
 				var c = e.className || "";
-				if ( ( m = re.exec( c ) ) && ( ltr = m[ 2 ] ) ) {
+				if ( c && ( m = re.exec( c ) ) && ( ltr = m[ 2 ] ) ) {
 					// We found a parent with a theme class
 					// on it so bail from this loop.
 					break;
 				}
+
 				e = e.parentNode;
 			}