计算动态添加的输入中的值

Question

我正在尝试构建一个允许用户动态添加额外行的水电费计算器。每行将有 3 个字段：瓦数、每天使用的小时数和总瓦数*小时数。第一行一切正常，但是当我尝试动态添加额外的行时，我的代码仍然适用于第一个产品并给了我一个 NaN。理想情况下，一旦他们完成添加行，我会在底部总结总千瓦时。下面粘贴的是我到目前为止的内容：

<html>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function(){
var maxField = 30; //Input fields increment limitation
var addButton = $('.add_button'); //Add button selector
var wrapper = $('.field_wrapper'); //Input field wrapper
var fieldHTML = '<div>Wattage: <input type="text"  name="field_wattage" value="300" size=4 maxlength="4" onchange="product()"> Hours Per Day Used: <select name="field_hour" onchange="product()"><option value="01"> 01</option><option value="02"> 02</option><option value="03"> 03</option><option value="04"> 04</option><option value="05"> 05</option><option value="06"> 06</option><option value="07"> 07</option><option value="08"> 08</option><option value="09"> 09</option><option value="10"> 10</option><option value="11"> 11</option><option value="12"> 12</option><option value="13"> 13</option><option value="14"> 14</option><option value="15"> 15</option><option value="16"> 16</option><option value="17"> 17</option><option value="18"> 18</option><option value="19"> 19</option><option value="20"> 20</option><option value="21"> 21</option><option value="22"> 22</option><option value="23"> 23</option><option value="24"> 24</option></select> Daily Wattage: <INPUT TYPE="text" ID="dailyproduct" NAME="result" VALUE=""/><a href="javascript:void(0);" class="remove_button" title="Remove field"> Remove Line</a></div>'; //New input field html 
var x = 1; //Initial field counter is 1
$(addButton).click(function(){ //Once add button is clicked
    if(x < maxField){ //Check maximum number of input fields
        x++; //Increment field counter
        $(wrapper).append(fieldHTML);
        // Add field html
    }
});
$(wrapper).on('click', '.remove_button', function(e){ //Once remove button is clicked
    e.preventDefault();
    $(this).parent('div').remove(); //Remove field html
    x--; //Decrement field counter
});
});
</script>
    <script type="text/javascript">
      function product()
      {

         var num1 = document.myform.field_wattage.value;
         var num2 = document.myform.field_hour.value;
         var myproduct = parseInt(num1) * parseInt(num2);
         document.getElementById('dailyproduct').value = myproduct;

      }
    </script>
<?php


echo "<br>";
echo "</select>";
echo "<br>";
$dateStart = mktime(0, 0, 0, 03, 01);
$dateEnd = mktime(0, 0, 0, 10, 31);

if (time() < $dateEnd && time() > $dateStart)
// show stuff
echo "You are in Peak Hours";
else
echo "You are in Off Peak Hours";


?>
<body>
<FORM NAME="myform">
<br />
<br />
<br />
<div class="field_wrapper">
<div>
    Wattage: 
    <input type="text" name="field_wattage" value="300" size=4 maxlength="4" onchange="product()">
    </select> Hours Per Day Used: 
    <select name="field_hour" onchange="product()"/>
    <option value="01"> 01</option>
    <option value="02"> 02</option>
    <option value="03"> 03</option>
    <option value="04"> 04</option>
    <option value="05"> 05</option>
    <option value="06"> 06</option>
    <option value="07"> 07</option>
    <option value="08"> 08</option>
    <option value="09"> 09</option>
    <option value="10"> 10</option>
    <option value="11"> 11</option>
    <option value="12"> 12</option>
    <option value="13"> 13</option>
    <option value="14"> 14</option>
    <option value="15"> 15</option>
    <option value="16"> 16</option>
    <option value="17"> 17</option>
    <option value="18"> 18</option>
    <option value="19"> 19</option>
    <option value="20"> 20</option>
    <option value="21"> 21</option>
    <option value="22"> 22</option>
    <option value="23"> 23</option>
    <option value="24"> 24</option>
    </select>
    Daily Wattage: 
    <INPUT TYPE="text" ID="dailyproduct" NAME="dailyproduct" VALUE=""/>
    <INPUT TYPE="button" NAME="button" Value="=" onClick="product()"/>
    <a href="javascript:void(0);" class="add_button" title="Add field"> Add Line</a>
</div>
</div>
</FORM>
</div>
</body>
</html>

我整个早上都在这里搜索，但没有找到任何能完全描述我的问题的内容。提前致谢。

Answer 1

我在下面创建了一个工作示例。正如我在评论中所述，您是按名称引用字段，当页面上有相同名称的字段时，这不起作用。

为了更现代的解决问题，你应该使用event delegation and determine which fields to update within the event. In the example, I have written one event to handle the select and input changes, then I use jQuery's .closest()方法来帮助我找到需要更新的字段。

$(document).ready(function(){
  var maxField = 30; //Input fields increment limitation
  var addButton = $('.add_button'); //Add button selector
  var wrapper = $('.field_wrapper'); //Input field wrapper
  var fieldHTML = '<div>Wattage: <input type="text"  name="field_wattage" value="300" size=4 maxlength="4"> Hours Per Day Used: <select name="field_hour"><option value="01"> 01</option><option value="02"> 02</option><option value="03"> 03</option><option value="04"> 04</option><option value="05"> 05</option><option value="06"> 06</option><option value="07"> 07</option><option value="08"> 08</option><option value="09"> 09</option><option value="10"> 10</option><option value="11"> 11</option><option value="12"> 12</option><option value="13"> 13</option><option value="14"> 14</option><option value="15"> 15</option><option value="16"> 16</option><option value="17"> 17</option><option value="18"> 18</option><option value="19"> 19</option><option value="20"> 20</option><option value="21"> 21</option><option value="22"> 22</option><option value="23"> 23</option><option value="24"> 24</option></select> Daily Wattage: <INPUT TYPE="text" NAME="dailyproduct" VALUE=""/><a href="javascript:void(0);" class="remove_button" title="Remove field"> Remove Line</a></div>'; //New input field html 
  var x = 1; //Initial field counter is 1
  $(addButton).click(function(){ //Once add button is clicked
    if(x < maxField){ //Check maximum number of input fields
      x++; //Increment field counter
      $(wrapper).append(fieldHTML);
      // Add field html
    }
  });
  $(wrapper).on('click', '.remove_button', function(e){ //Once remove button is clicked
    e.preventDefault();
    $(this).parent('div').remove(); //Remove field html
    x--; //Decrement field counter
  });
});

$(".field_wrapper").on("change", "input,select", function() {
  var parent = $(this).closest("div");
  var num1 = parent.find('[name="field_wattage"]').val();
  var num2 = parent.find('[name="field_hour"]').val();
  var dailyproduct = parent.find('[name="dailyproduct"]');
  var myproduct = parseInt(num1) * parseInt(num2);
  dailyproduct.val(myproduct);
  getTotal();
});

function getTotal() {
 var total = 0;
 $('[name="dailyproduct"]').each(function() {
   total += (parseInt(this.value, 0) || 0);
 });
 $("#total").val(total);
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<div class="field_wrapper">
  <div>
    Wattage: 
    <input type="text" name="field_wattage" value="300" size=4 maxlength="4" />
    Hours Per Day Used: 
    <select name="field_hour">
      <option value="01"> 01</option>
      <option value="02"> 02</option>
      <option value="03"> 03</option>
      <option value="04"> 04</option>
      <option value="05"> 05</option>
      <option value="06"> 06</option>
      <option value="07"> 07</option>
      <option value="08"> 08</option>
      <option value="09"> 09</option>
      <option value="10"> 10</option>
      <option value="11"> 11</option>
      <option value="12"> 12</option>
      <option value="13"> 13</option>
      <option value="14"> 14</option>
      <option value="15"> 15</option>
      <option value="16"> 16</option>
      <option value="17"> 17</option>
      <option value="18"> 18</option>
      <option value="19"> 19</option>
      <option value="20"> 20</option>
      <option value="21"> 21</option>
      <option value="22"> 22</option>
      <option value="23"> 23</option>
      <option value="24"> 24</option>
    </select>
    Daily Wattage: 
    <INPUT TYPE="text" NAME="dailyproduct" VALUE=""/>
    <a href="javascript:void(0);" class="add_button" title="Add field"> Add Line</a>
  </div>
</div>

<label>
  Total:
  <input id="total" />
</label>

计算动态添加的输入中的值

calculating values in dynamically added inputs

html

javascript

arrays

dynamic