javascript select change field price with discount onchange [closed]

Answer 1

This should work for you.

JSFiddle

HTML

Discount:

   5% discount
   10% discount
    20% discount


Price:

JavaScript

function updateInput(){
    //get the current amount from the 'discount' field
    var discount = document.getElementsByName("discount")[0].value;
    //get the current amount from the 'price' field
    var currentPrice = document.getElementsByName("price")[0].value;
    //new price should be "old price" - "discount%" * "old price"
    document.getElementsByName("price")[0].value =  currentPrice - ((discount/100) * currentPrice);
}