Order Form with Running Total?

Hey All,

Does any know of a plugin (not necessarily for WordPress) which works using some jquery or ajax and sets a running total for an order form?

Such an example would be:

https://www.psdtoxhtml.co.uk/psd-to-html/order-psd-to-html.html

The attachment feature is great along with the rest of the form and would love to know how to do this.

There isn’t too much info out there… unless I am searching with the wrong terms.