javascript select change field price with discount onchange [closed]

Answer 1

With jQuery:

$("select").on("change", function() {
    var discount = $(this).val();
    // ensure discount is a number
    discount = parseInt(discount) || 100;

    var price = $("input[name='price']").data("price");
    // ensure price is a number
    price = parseFloat(price) || 0;

    // calculate new price
    price = price * discount / 100;

    // set the price
    $("input[name='price']").val(price.toFixed(2));
});

$(document).ready(function() {
    // store initial price
    $("input[name='price']").data("price", $("input[name='price']").val());

    // trigger change on load to have your initial value
    $("select").trigger("change");
});