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Петрович's questions

Martin Hope
Петрович
Asked: 2025-01-27 02:43:27 +0000 UTC
  • 4

你好。

在 bootstrap 5 中有这样一个东西，form-check form-switch它有一个属性checked

问题是如何捕捉开/关值。使用 JS。addEventListener没有帮助

<div class="form-check form-switch">
  <input class="form-check-input" type="checkbox" role="switch" id="flexSwitchCheckDefault">
  <label class="form-check-label" for="flexSwitchCheckDefault">Default switch checkbox input</label>
</div>
javascript
Martin Hope
Петрович
Asked: 2025-01-11 01:10:23 +0000 UTC
  • 5

我无法理解。为什么普通函数的结果是未定义的，而箭头函数的结果是预期的结果？

let testArr = [
  [1,2,3],
  [4,5,6],
  [7,8,9],
]

console.log (testArr)

let sumArr = testArr.map(function(item){
  item.reduce(function(acc, item){
    return acc + item;   
  })
})
console.log (sumArr)

let sumArr1 = testArr.map(item => item.reduce((acc, item) => acc + item));

console.log (sumArr1)
javascript
Martin Hope
Петрович
Asked: 2025-01-05 19:56:52 +0000 UTC
  • 6

最近在学JS。帮我解决以下问题：

有一个 NodeList，您需要从中提取 ID 及其值。您需要获取 3 个数组（按 ID），从中提取 VALUE

ID 看起来像这样：

visota_proema_custom_порядковый номер  
shirina_proema_custom_порядковый номер  
kolich_proema_custom_порядковый номер

我试过这个

let customProem = Array.from (document.querySelectorAll('[id*="_proema_custom"]'));
 

  let result = customProem.filter(function(val){
   return val == visota_proema_custom1;

    
  })
  console.log (customProem);
  console.log (result);
<div class="row">
  <div id="orig_inp">
  </div>
  <div id="custom_proem_2">
    <div>
      <div class="input-group m-3">
        <span class="input-group-text">Высота проема, м</span>
        <input id="visota_proema_custom2" value="1.6" type="number" class="form-control">
      </div>
    </div>
    <div>
      <div class="input-group m-3">
        <span class="input-group-text">Ширина проема, м</span>
        <input id="shirina_proema_custom2" value="1.8" type="number" class="form-control">
      </div>
    </div>
    <div>
      <div class="input-group m-3">
        <span class="input-group-text">Количество, шт</span>
        <input id="kolich_proema_custom2" value="3" type="number" class="form-control">
      </div>
    </div>
  </div>
  <div id="custom_proem_1">
    <div>
      <div class="input-group m-3">
        <span class="input-group-text">Высота проема, м</span>
        <input id="visota_proema_custom1" value="1.6" type="number" class="form-control">
      </div>
    </div>
    <div>
      <div class="input-group m-3">
        <span class="input-group-text">Ширина проема, м</span>
        <input id="shirina_proema_custom1" value="1.8" type="number" class="form-control">
      </div>
    </div>
    <div>
      <div class="input-group m-3">
        <span class="input-group-text">Количество, шт</span>
        <input id="kolich_proema_custom1" value="3" type="number" class="form-control">
      </div>
    </div>
  </div>
</div>

javascript