diff --git a/assets/js/frontend/woocommerce.js b/assets/js/frontend/woocommerce.js
index cdb8d0c4903..0168b4a7b5f 100644
--- a/assets/js/frontend/woocommerce.js
+++ b/assets/js/frontend/woocommerce.js
@@ -32,7 +32,7 @@ jQuery(document).ready(function($) {
 	    if ( ! currentVal || currentVal == "" || currentVal == "NaN" ) currentVal = 0;
 	    if ( max == "" || max == "NaN" ) max = '';
 	    if ( min == "" || min == "NaN" ) min = 0;
-	    if ( step == 'any' || step == "" || parseFloat( step ) == "NaN" ) step = 1;
+	    if ( step == 'any' || step == "" || step == undefined || parseFloat( step ) == "NaN" ) step = 1;
 	    
 	    // Change the value
 	    if ( $(this).is('.plus') ) {