Hi, Sagar.
I recommend that you first confirm that the 2nd bar code has a different value than the 1st bar code. To check the two values, you could insert:
console.log("itemObj1.productBcid = " + itemObj1.productBcid);
immediately before the following line:
if ($w('#an1').value === "") {
and then check the (Developer Tools) console after running your code.
HTH,
Art Bergquist