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javascript - 如何在 HTML 中的按钮之前在 JavaScript 中添加一个按钮？

问题描述

我正在尝试制作某种计算器，但我想将 javascript 中的按钮放在我用 HTML 制作的按钮之前。

我想要我的记忆按钮（MS、MC、MR），在我的清除按钮（C）之前，我一直在尝试一切，但似乎有点难过。

我一直在尝试使用 insertBefore() 方法，但我认为我做错了。谢谢，

JavaScript（底部是我的错误）：

//3.
//Changing colors of opertion colors 

//Multiply Color
const colorMultiply = document.getElementById('multiply')
colorMultiply.style.backgroundColor = "green"

//Divide Color
const colorDivide = document.getElementById('divide')
colorDivide.style.backgroundColor = "red"

//subtract color
const colorSubtract = document.getElementById('subtract')
colorSubtract.style.backgroundColor="blue"

//add color
const colorAdd = document.getElementById('add')
colorAdd.style.backgroundColor="yellow"


//change font of numbers to blue (I did it like this incase anyone wants to color of a single number)
const number1 = document.getElementById('number1')
number1.style.color="blue"
const number2 = document.getElementById('number2')
number2.style.color="blue"
const number3 = document.getElementById('number3')
number3.style.color="blue"
const number4 = document.getElementById('number4')
number4.style.color="blue"
const number5 = document.getElementById('number5')
number5.style.color="blue"
const number6 = document.getElementById('number6')
number6.style.color="blue"
const number7 = document.getElementById('number7')
number7.style.color="blue"
const number8 = document.getElementById('number8')
number8.style.color="blue"
const number9 = document.getElementById('number9')
number9.style.color="blue"
const number0 = document.getElementById('number0')
number0.style.color="blue"
const decimal = document.getElementById('decimal')
decimal.style.color="blue"

//Changing color of the clear button
const clear = document.getElementById('clear')
clear.style.color="white"
clear.style.backgroundColor="black"
///////////////////////////////////////////////////////////////////////////////////////////////////////
/*
var memoryStoreButton = document.createElement('BUTTON')
memoryStoreButton.innerHTML = "MS"
document.body.appendChild(memoryStoreButton)


var memoryClearButton = document.createElement('BUTTON')
memoryClearButton.innerHTML = "MC"
document.body.appendChild(memoryClearButton)

var memoryRestoreButton = document.createElement('BUTTON')
memoryRestoreButton.innerHTML = "MR"
document.body.appendChild(memoryRestoreButton)
*/

HTML：

<!DOCTYPE html>
<html lang="en">

<head>
 <meta charset="UTF-8">
 <meta name="viewport" content="width=device-width, initial-scale=1.0">
 <meta http-equiv="X-UA-Compatible" content="ie=edge">

<title> Calculator 8 </title>
 <script src="fp.js" defer></script>
 <link rel="stylesheet" href="fp.css">



</head>

<body>
 <section class="calculator8">
    <h1> Calculator 8 </h1>
  <form>
   <input type="text" name="" id="" class="screen8">
  </form>
  <div class="buttons8"> 
   <!-- operation buttons -->
   <button id="multiply" type="button" class="btn8 btn-mul" data-num="*">*</button>
   <button id="divide" type="button" class="btn8 btn-div" data-num="/">/</button>
   <button id="subtract" type="button" class="btn8 btn-sub" data-num="-">-</button>
   <button id="add" type="button" class="btn8 btn-add" data-num="+">+</button>
   <!-- number buttons -->
   <button id="decimal" type="button" class="btn8 btn-grey" data-num=".">.</button>
   <button id="number9" type="button" class="btn8 btn-grey" data-num="9">9</button>
   <button id="number8" type="button" class="btn8 btn-grey" data-num="8">8</button>
   <button id="number7" type="button" class="btn8 btn-grey" data-num="7">7</button>
   <button id="number6" type="button" class="btn8 btn-grey" data-num="6">6</button>
   <button id="number5" type="button" class="btn8 btn-grey" data-num="5">5</button>
   <button id="number4" type="button" class="btn8 btn-grey" data-num="4">4</button>
   <button id="number3" type="button" class="btn8 btn-grey" data-num="3">3</button>
   <button id="number2" type="button" class="btn8 btn-grey" data-num="2">2</button>
   <button id="number1" type="button" class="btn8 btn-grey" data-num="1">1</button>
   <button id="number0" type="button" class="btn8 btn-grey" data-num="0">0</button>
   <button id="equals" type="button" class="btn8  btn-grey">=</button>
   <button id="clear" type="button" class="btn8  btn-grey">C</button>


  </div>



 </section>


</body>

</html>

标签： javascripthtmlcssevents

解决方案

为什么要尝试动态插入按钮？我想你想切换扩展控件。

用 javascript 做这件事很讨厌。

只需将所有 html 按钮放入并使用 css 显示/隐藏您要切换的按钮。

使用 Javascript 切换容器上的 css 类

<button id="mc" type="button" class="btn8 btn-grey advanced">MC</button>

.calculator8 .advanced { display: none; }
.calculator8.showAdvanced .advanced { display: block; }

document.querySelector('.calulator8').classList.toggle("showAdvanced")

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