I need a plugin/script for Virtuemart 2.
There are some product, which have length calculated price.
So I need option, when buyer add length in m (max 2decimals) in a input field (custom field) and the price is calculated in the product details page. (there are needed validation for min, especially max length).
...if then buyer want, can choose color for example without problem (dont change the price). Finally in the cart (invoice) must show the length too.
There are products which dont need this option.
The solution must be compatible with all browsers.