Question

我坚持用javascript计算价格。如果我喜欢按钮，它会打印价格，但点击两次后显示相同的价格。但它需要是例如：39 + 39 + 39 =价格。但它只显示39 ..

document.getElementById("btn").onclick = function()
{
     price ();
}

function price()
{
     var type = document.getElementById("tickettype").value;
     var price;

     switch(type)
     {
          case "normal":
          price=39;
          break;

          case "vip":
          price=99;
          break;
     }

     var totaal = price;

     printPrice(totaal);
}

function printPrice(p_totaal)
{
     document.getElementById("totalprice").innerHTML = p_totaal;
}

Answer 1

您必须在total范围之外定义price()变量，例如：

document.getElementById("btn").onclick = function()
{
     price ();
}
var totaal = 0; // Changed here
function price()
{
     var type = document.getElementById("tickettype").value;
     var price;

     switch(type)
     {
          case "normal":
          price=39;
          break;

          case "vip":
          price=99;
          break;
     }
     totaal += price; // Changed here
     printPrice(totaal);
}

function printPrice(p_totaal)
{
     document.getElementById("totalprice").innerHTML = p_totaal;
}

您所做的是重新定义变量，而不是增加全局变量。

Answer 2

将其存储在函数范围之外的变量中：

var currPrice = 0;
document.getElementById("btn").onclick = function()
{
     price ();
}

function price()
{
     var type = document.getElementById("tickettype").value;
     var price;

     switch(type)
     {
          case "normal":
          price=39;
          break;

          case "vip":
          price=99;
          break;
     }
     currPrice = currPrice + price;

     printPrice(currPrice);
}

function printPrice(p_totaal)
{
     document.getElementById("totalprice").innerHTML = p_totaal;
}

Answer 3

其他答案都是正确的。您还可以删除switch语句，只使用故障单类型和价格之间的映射：

var total = 0;
var ticket_prices = {
    'normal': 39,
    'vip': 99
};

document.getElementById('btn').onclick = function() {
    var type = document.getElementById('tickettype').value;
    var price = ticket_prices[type];
    total += price;

    document.getElementById('totalprice').innerHTML = total;
}

计算价格javascript

3 个答案: