Update price automatically when quantity changed on product page Magento

Question

I am looking to have the product price automatically updated based on the quantity the customer has chosen.

Currently when you choose a custom option in magento the

Answer 1

In Magento 1.9.2.4, the code file to edit is js/varien/product.js

In Magento 1.9.3 and above, the file to edit is js/varien/product_options.js

Add the following code:

var qty;
if($('qty').getValue().length == 0 || isNaN($('qty').getValue()) || $('qty').getValue() <= 0) { 
    qty = 1;
} else { 
    qty = $('qty').getValue();
    price *= qty;
}

right after

if (price < 0) price = 0;

and before

if (price > 0 || this.displayZeroPrice) { ...

And, at the end of the file add:

Event.observe(window, 'load', function() {
    $('qty').observe('blur', function(e){
        optionsPrice.reload();
    });
});

Source: https://magentojai.blogspot.com/2015/06/price-update-while-change-qty-in.html