javascript - 取钱有困难吗？

Question

出于某种原因，我的代码只是不想计算。我正在练习一本练习书，但在这方面它并没有真正帮助我。对于总和，我得到类似 20000NaN 的东西，我知道这不是一个数字。我怎样才能让它正确计算？我尝试使用 ParseFloat 来转换我的百分比。谢谢。

<form action="#" name="car">
        <p>&nbsp;</p>
        <p>Vehicle:
          <select id="dropDown1">
            <option selected value="370z, 20000, 10%, 8.5%">Accord</option>
            <option value="M3, 18000, 8%, 8.5%">Altima</option>
            <option value="Camaro, 19000, 9%, 8.5%">Camry</option>
          </select>
        <br />
        <br />
        </p>
        <button type="button" onclick="car()" value="Submit">Book it now</button>
        <br />
        <br />
        <textarea name="answer" cols="80" rows="3" disabled></textarea>
        <br />
        <br />
    </form>
</div>

<script language="javaScript">
    function car() {
        var value = document.getElementById("dropDown1").value;
        var split = value.split(",");
        var v1 = split[0];
        var v2 = split[1];
        var v3 = split[2];
        var v4 = split[3];
parseFloat(v3);
parseFloat(v4);
profit = v2*v3;
tax = v2*v4;
extra = profit+tax;
sum = v2 + extra;

            document.car.answer.value = "You selected " + v1 + " " + "which has a base price of" + v2 + ", a profit of" + v3 + ", and sales tax of" + v4 + "." + " Total cost of this vehicle, including profit and sales tax is: $" + sum + "."

    }

</script>

Answer 1

您的大部分语法都不正确。事情应该是这样的:

var test = function() {
        var value = document.getElementById("dropDown1").value;
        var split = value.split(",");
        var v1 = split[0];
        var v2 = split[1];
        var v3 = split[2];
        var v4 = split[3];
        v3 = parseFloat(v3);
        v4 = parseFloat(v4);
        var profit = parseFloat(v2)*parseFloat(v3)/100;
        var tax = parseFloat(v2)*parseFloat(v4)/100;
        var extra = parseFloat(profit)+parseFloat(tax);
        var sum = parseFloat(v2) + parseFloat(extra);
document.getElementById("answer").value = "You selected " + v1 + " " + "which has a base price of $" + v2 + ", a profit of " + v3 + "%, and sales tax of " + v4 + "%. Total cost of this vehicle, including profit and sales tax is: $" + sum + ".";
    };

<form action="#" name="car">
        <p>&nbsp;</p>
        <p>Vehicle:
          <select id="dropDown1">
            <option selected value="370z, 20000, 10%, 8.5%">Accord</option>
            <option value="M3, 18000, 8%, 8.5%">Altima</option>
            <option value="Camaro, 19000, 9%, 8.5%">Camry</option>
          </select>
        <br />
        <br />
        </p>
        <button type="button" onclick="test()" value="Submit">Book it now</button>
        <br />
        <br />
        <textarea id="answer" cols="80" rows="3" disabled></textarea>
        <br />
        <br />
    </form>