I have a line `<div class="price-box price-final_price" data-role="priceBox" data-product-id="176">` in a large html file.

I need to store the value of `product-id` inside a variable, so that I can access it globally.

I'm tring to do it with

```
var var_productid = document.querySelectorAll('div[data-role="priceBox"]')[0].data-product-id;

```

But it's not working. What am I doing wrong?