HTML+CSS+JS实现简易汇率计算器（使用Fetch）

还是github上找的小玩意跟着模仿着敲的。
首先看一下fetch，我也是学过ajax之后头一次见这玩意，然后就看着人家代码顺便上MDN看了一下。

Fetch API 提供了一个 JavaScript 接口，用于访问和操纵 HTTP 管道的一些具体部分，例如请求和响应。它还提供了一个全局 fetch() 方法，该方法提供了一种简单，合理的方式来跨网络异步获取资源。
反正这个东西好像就是比ajax要牛的东西？具体的还是MDN看一下文档吧

MDN-fetch链接

直接看最基本用法：

fetch('http://example.com/movies.json')
  .then(response => response.json())
  .then(data => console.log(data));

可以log看一下返回的东西就差不多知道咋用了吧

看一下汇率计算器

直接上源码

html代码

    "img/money.png" alt="">
    
Exchange Rate Calculator
    
"description">Choose the currency and the amounts to get the exchange rate
    
"container">
        
"top flex">
            "" id="choose-tb">
                "AED">AED
                "ARS">ARS
                "AUD">AUD
                "BGN">BGN
                "BRL">BRL
                "BSD">BSD
                "CAD">CAD
                "CHF">CHF
                "CLP">CLP
                "CNY">CNY
                "COP">COP
                "CZK">CZK
                "DKK">DKK
                "DOP">DOP
                "EGP">EGP
                "EUR">EUR
                "FJD">FJD
                "GBP">GBP
                "GTQ">GTQ
                "HKD">HKD
                "HRK">HRK
                "HUF">HUF
                "IDR">IDR
                "ILS">ILS
                "INR">INR
                "ISK">ISK
                "JPY">JPY
                "KRW">KRW
                "KZT">KZT
                "MXN">MXN
                "MYR">MYR
                "NOK">NOK
                "NZD">NZD
                "PAB">PAB
                "PEN">PEN
                "PHP">PHP
                "PKR">PKR
                "PLN">PLN
                "PYG">PYG
                "RON">RON
                "RUB">RUB
                "SAR">SAR
                "SEK">SEK
                "SGD">SGD
                "THB">THB
                "TRY">TRY
                "TWD">TWD
                "UAH">UAH
                "USD" selected="selected">USD
                "UYU">UYU
                "VND">VND
                "ZAR">ZAR
            
            "number" value="1" placeholder="0" id="input-tb">
        
        
"medium flex">
            "swapBtn">Swap
            
"rate">
        
        
"bottom flex">
            "" id="choose-db">
                "AED">AED
          "ARS">ARS
          "AUD">AUD
          "BGN">BGN
          "BRL">BRL
          "BSD">BSD
          "CAD">CAD
          "CHF">CHF
          "CLP">CLP
          "CNY">CNY
          "COP">COP
          "CZK">CZK
          "DKK">DKK
          "DOP">DOP
          "EGP">EGP
          "EUR" selected="selected">EUR
          "FJD">FJD
          "GBP">GBP
          "GTQ">GTQ
          "HKD">HKD
          "HRK">HRK
          "HUF">HUF
          "IDR">IDR
          "ILS">ILS
          "INR">INR
          "ISK">ISK
          "JPY">JPY
          "KRW">KRW
          "KZT">KZT
          "MXN">MXN
          "MYR">MYR
          "NOK">NOK
          "NZD">NZD
          "PAB">PAB
          "PEN">PEN
          "PHP">PHP
          "PKR">PKR
          "PLN">PLN
          "PYG">PYG
          "RON">RON
          "RUB">RUB
          "SAR">SAR
          "SEK">SEK
          "SGD">SGD
          "THB">THB
          "TRY">TRY
          "TWD">TWD
          "UAH">UAH
          "USD">USD
          "UYU">UYU
          "VND">VND
          "ZAR">ZAR
            
            "number" placeholder="0" id="input-db">
        
    
    

css代码

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

select:focus,
input:focus,
button:focus {
    outline: 0;
}

body {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f4f4f4;
}

img {
    width: 150px;
}

h1 {
    margin: 22px 0;
    color: rgb(47, 186, 158);
}

.description {
    margin: 16px 0;
}

select {
    padding: 9px 5px 9px 9px;
    font-size: 16px;
    background: transparent;
    border: 1px #dedede solid;
    border-radius: 5px;
}

input {
    font-size: 30px;
    text-align: right;
    border: 0;
    background: transparent;
}

.flex {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.top {
    padding: 40px 0;
}

.swapBtn {
    padding: 5px 12px;
    background-color: rgb(47, 186, 158);
    color: #fff;
    border-radius: 5px;
}

.rate {
    color: rgb(47, 186, 158);
    font-size: 14px;
    padding: 0 10px;
}

.bottom {
    padding: 40px 0;
}

js代码

var selectTb = document.querySelector('#choose-tb')
var selectDb = document.querySelector('#choose-db')
var inputTb = document.querySelector('#input-tb')
var inputDb = document.querySelector('#input-db')
var swapBtn = document.querySelector('.swapBtn')
var rateData = document.querySelector('.rate')

function calculate() {
    fetch('https://open.exchangerate-api.com/v6/latest')
        .then(res => res.json())
        .then(data => {
            rate = data.rates[selectDb.value] / data.rates[selectTb.value]
            rateData.innerText = `1${selectTb.value}=${rate} * ${selectDb.value}`
            inputDb.value = (inputTb.value * rate).toFixed(2)
        })
}
selectTb.addEventListener('change', calculate)
selectDb.addEventListener('change', calculate)
inputTb.addEventListener('input', calculate)
inputDb.addEventListener('input', calculate)

swapBtn.addEventListener('click', () => {
    var temp = selectDb.value
    selectDb.value = selectTb.value
    selectTb.value = temp
    calculate()
})

calculate()

API用的是人家原来项目上的，所以这个汇率八成不太符合实际吧。