JSFiddle - React, Tailwind, and code Playground

by radu

HTML

<input type="text" id="user_input"/>
<p id="price_output"></p>

JavaScript

$(function() { 
    var tier_prices = [
    [100, 20],
    [200, 15],
    [500, 10]
];

$('#user_input').change(function() {
    var num = parseInt($(this).val(), 10),
        price = 0;

    for (var i = tier_prices.length; i >= 0; i--) {
        if (num <= tier_prices[i][0]) {
            price = tier_prices[i][1];
        }
    }

    $('#price_output').text(price * num);
});
});