diff --git a/html/javascript/listing.js b/html/javascript/listing.js
index 5d1c0bc..6275ffe 100644
--- a/html/javascript/listing.js
+++ b/html/javascript/listing.js
@@ -112,7 +112,7 @@ function show(){
 function getUnavailableItems(){
 	var unavailable = new Array;
 	var unavailable_str = localStorage.getItem('unavailable');
-	if(unavailable_str !== ""){
+	if(unavailable_str !== "" && unavailable_str !== null){
 		unavailable = JSON.parse(unavailable_str);
 	}
 	return unavailable;
diff --git a/html/javascript/request.js b/html/javascript/request.js
index 6279c41..41018f2 100644
--- a/html/javascript/request.js
+++ b/html/javascript/request.js
@@ -119,7 +119,7 @@ function getCartItems(){
 	//get them from local storage
     var cart_str = localStorage.getItem('cart');
 	//if there is at least one object already we need to convert it from JSON to string
-    if (cart_str !== null) {
+    if (cart_str !== null && cart_str !== "") {
         cart = JSON.parse(cart_str);
     }
     return cart;
@@ -128,7 +128,7 @@ function getCartItems(){
 function getUnavailableItems(){
 	var unavailable = new Array;
 	var unavailable_str = localStorage.getItem('unavailable');
-	if(unavailable_str !== ""){
+	if(unavailable_str !== "" && unavailable_str !== null){
 		unavailable = JSON.parse(unavailable_str);
 	}
 	return unavailable;
diff --git a/html/javascript/return.js b/html/javascript/return.js
index c296d8b..6298caa 100644
--- a/html/javascript/return.js
+++ b/html/javascript/return.js
@@ -204,7 +204,7 @@ function getUnavailableIDs()
 {
 	var unavailable = new Array;
 	var unavailable_str = localStorage.getItem('unavailable');
-	if(unavailable_str !== ""){
+	if(unavailable_str !== "" && unavailable_str !== null){
 		unavailable = JSON.parse(unavailable_str);
 	}
 	return unavailable;
diff --git a/html/javascript/shoppingCart.js b/html/javascript/shoppingCart.js
index de1e66e..498d818 100644
--- a/html/javascript/shoppingCart.js
+++ b/html/javascript/shoppingCart.js
@@ -224,7 +224,7 @@ This function gets unavailable items from local storage.
 function getUnavailableItems(){
 	var unavailable = new Array;								//make new array
 	var unavailable_str = localStorage.getItem('unavailable');	//get the string from local storage
-	if(unavailable_str !== ''){								//as long as its not null
+	if(unavailable_str !== '' && unavailable_str !== null){								//as long as its not null
 		unavailable = JSON.parse(unavailable_str);				//make into array
 	}
 	return unavailable;											//return value is an array