在javascript中计算多个项目的总价格和数量的最简单方法是什么？

Question

I have a number of inputs such as:

<input type="number" name="qty[]" data-price="123.99" value="0" class="qtyfield" min="0">
<input type="number" name="qty[]" data-price="222.11" value="0" class="qtyfield" min="0">
<input type="number" name="qty[]" data-price="25.68" value="0" class="qtyfield" min="0">

if someone selects a quantity from the first one of 6 and the second example of quantity of 8 I need a running total to be calculated as any changes occur.

Answer 1

If the point here is to get running total of your quantities, weighted by data-price value, you may simply listen for changes and update result value with reduce() 'ed sum of input field multiplied by data-price :

 $('.qtyfield').on('change', () => { const total = [...$('.qtyfield')] .map(input => $(input).val()*$(input).attr('data-price')) .reduce((t,q) => t+q,0) $('#result').text(total) })

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <input type="number" name="qty[]" data-price="1" value="0" class="qtyfield" min="0"> <input type="number" name="qty[]" data-price="2" value="0" class="qtyfield" min="0"> <input type="number" name="qty[]" data-price="3" value="0" class="qtyfield" min="0"> <div id="result"></div>

Note: I have changed data-price values for simplicity sake