复选框计算不起作用答案

【问题标题】：Checkbox calculation not working复选框计算不起作用
【发布时间】：2014-11-17 22:12:04
【问题描述】：

$(document).ready(function() {
  $("input[type=checkbox]").on("change", function() {
    var tot = 0;
    $("input[type=checkbox]:checked").each(function() {
      tot += +(this.value);
    });
    $("#result").text("Total = " + tot);
    $('#CRCGCA').val("Total = " + tot)
  });
});

<p>Gift Certificate Amount (check one or more)
  <br />
  <span class="wpcf7-form-control-wrap GRCGA"><span class="wpcf7-form-control wpcf7-checkbox wpcf7-validates-as-required Multiple radio-vertical" id="GRCGA"><span class="wpcf7-list-item first"><label><input type="checkbox" name="GRCGA[]" value="$10.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$10.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$20.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$20.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$25.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$25.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$40.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$40.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$100.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$100.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$200.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$200.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$400.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$400.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item last"><label><input type="checkbox" name="GRCGA[]" value="$500.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$500.00 Gift Card</span>
  </label>
  </span>
  </span>
  </span>
</p>
<p>Gift Card Amount: <span class="wpcf7-form-control-wrap CRCGCA"><input type="text" name="CRCGCA" value="" size="8" maxlength="8" class="wpcf7-form-control wpcf7-text" id="CRCGCA" aria-invalid="false" /></span>
</p>

<p id="result"></p>

我在计算复选框组的总数时遇到问题（此复选框集是多选的（可以选择一个或多个）我还希望将总数复制到名为礼品卡金额的文本框中。

HTML：

<p>
    Gift Certificate Amount (check one or more)<br />
    [checkbox* GRCGA id:GRCGA class:Multiple use_label_element class:radio-vertical "$10.00 Gift Card " "$20.00 Gift Card " "$25.00 Gift Card " "$40.00 Gift Card " "$100.00 Gift Card " "$200.00 Gift Card " "$400.00 Gift Card " "$500.00 Gift Card"] 
</p>   
Gift Card Amount: [text CRCGCA 8/8 id:CRCGCA]
<p id="result"></p>

JavaScript

$(document).ready(function() {
    $("input[type=checkbox]").on("change", function() {
        var tot = 0;

        $("input[type=checkbox]:checked").each(function() {
            tot += +(this.value);
        });

        $("#result").text("Total = " + tot);
        $('#CRCGCA').val("Total = " + tot)         
    });
});

【问题讨论】：

可以加jsfiddle吗？
请显示（相关的，最小的）HTML。可能还有一个 Stack Snippet，用于演示您的代码的作用（在问题编辑器中，文本区域上方的图像图标旁边带有铅笔的按钮）。
感谢您让我知道如何做这个我从来不知道的小 sn-p。我编辑了我的问题。

标签： javascript checkbox calculated-field subtotal

【解决方案1】：

您的复选框具有$25.00 Gift Card 之类的值。您需要将其更改为数字，例如25.

如果您坚持使用当前标记，您可以使用获得实际数字

var val = this.value.substr(1).split(' ')[0];
tot += +(val);

虽然擅长正则表达式的人可能会发现更漂亮的东西。

【讨论】：

有没有办法允许值
是的，使用JS可以将最终输出金额转换为$。
@Annie 你的意思是保持值不变，但仍然计算总和？
去掉第二行输入并添加
找出$符号

【解决方案2】：

一种方法，使用String.prototype.match() 和Array.prototype.reduce()：

$(document).ready(function() {
  $("input[type=checkbox]").on("change", function() {
    // concatenating a currency symbol to the result of mapping the checked checkboxes:
    var total = '$' + $('input[type="checkbox"]:checked').map(function(){
      // matching one-or-more numbers ('\d+') followed by a (literal) period ('\.')
      // followed by one-or-more numbers:
      var n = this.value.match(/\d+\.\d+/);
      // if there was a match (and 'n' is therefore not-null), and has a length,
      // we parseFloat that matched number string, otherwise we return 0:
      return n && n.length ? parseFloat(n[0]) : 0;
    // get() converts the 'map' into an array:
    }).get()
    // reduce() sums together the array-elements ('a + b'):
    .reduce(function (a, b) {
      return a + b;
      // '0' is the supplied starting value for reduce():
    }, 0)
    // toFixed(2) converts the number to a string, with two decimal places:
    .toFixed(2);

    $("#result").text("Total = " + total);
    $('#CRCGCA').val("Total = " + total)
  });
});

$(document).ready(function() {
  $("input[type=checkbox]").on("change", function() {
    var total = '$' + $('input[type="checkbox"]:checked').map(function(){
      var n = this.value.match(/\d+\.\d+/);
      return n && n.length ? parseFloat(n[0]) : 0;
    }).get().reduce(function (a, b) {
      return a + b;
    }, 0).toFixed(2);
    $("#result").text("Total = " + total);
    $('#CRCGCA').val("Total = " + total)
  });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>Gift Certificate Amount (check one or more)
  <br />
  <span class="wpcf7-form-control-wrap GRCGA"><span class="wpcf7-form-control wpcf7-checkbox wpcf7-validates-as-required Multiple radio-vertical" id="GRCGA"><span class="wpcf7-list-item first"><label><input type="checkbox" name="GRCGA[]" value="$10.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$10.0 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$20.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$20.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$25.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$25.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$40.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$40.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$100.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$100.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$200.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$200.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item"><label><input type="checkbox" name="GRCGA[]" value="$400.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$400.00 Gift Card</span>
  </label>
  </span><span class="wpcf7-list-item last"><label><input type="checkbox" name="GRCGA[]" value="$500.00 Gift Card" />&nbsp;<span class="wpcf7-list-item-label">$500.00 Gift Card</span>
  </label>
  </span>
  </span>
  </span>
</p>
<p>Gift Card Amount: <span class="wpcf7-form-control-wrap CRCGCA"><input type="text" name="CRCGCA" value="" size="8" maxlength="8" class="wpcf7-form-control wpcf7-text" id="CRCGCA" aria-invalid="false" /></span>
</p>

<p id="result"></p>

参考资料：

JavaScript：
- Array.prototype.reduce()。
- JavaScript regular expressions。
- Number.prototype.toFixed()。
- parseFloat()。
- String.prototype.match()。
jQuery:
- get()。
- map()。
- text()。
- val()。

【讨论】：