添加复选框值并写入输入字段

Question

我有一个带有一些复选框和 Javascript sn-p 的表单，其中复选框值被累加并写入 <span>。这很好用，但我真的希望它写入输入文本字段而不是 <span>。

这是我表单的复选框部分：

<section id="extra-features">
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="outside" class="sum" value="10" data-toggle="checkbox"> Outside Wash</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="aclean" class="sum" value="39" data-toggle="checkbox"> A - Clean: Wash Vacuum, Windows, Wheels/Tires, Wax</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="bclean" class="sum" value="0" data-toggle="checkbox"> B - Clean: Same as A above <em>PLUS:</em> Shampoo Interior, Clean/Dress Interior Panels, Remove Bugs/Tar.</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="cclean" class="sum" value="109" data-toggle="checkbox"> C - Clean: Same as B above <em>PLUS:</em> Compound Polish Exterior, Clean/Dress Moldings as Needed.    </label>
</div>
</section>

这是 javascript 当前正在写入的 <span>：

<span id="payment-total" style="text-decoration:underline;">0</span>

这里是javascript：

window.onload=function(){
var inputs = document.getElementsByClassName('sum'),
    total  = document.getElementById('payment-total');

 for (var i=0; i < inputs.length; i++) {
    inputs[i].onchange = function() {
        var add = this.value * (this.checked ? 1 : -1);
        total.innerHTML = parseFloat(total.innerHTML) + add
    }
  }
}

Answer 1

你不需要循环。使用 jQuery 的 change() 而不是 onchange。它有一个隐式循环。使用 jQuery 进行检查输入也比定制的 JS 更可靠。这是一个最小的工作示例：

$(document).ready(function() {
    function updateSum() {
      var total = 0;
      $(".sum:checked").each(function(i, n) {total += parseInt($(n).val());})
      $("#total").val(total);
    }
    // run the update on every checkbox change and on startup
    $("input.sum").change(updateSum);
    updateSum();
})

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<section id="extra-features">
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="outside" class="sum" value="10" data-toggle="checkbox"> Outside Wash</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="aclean" class="sum" value="39" data-toggle="checkbox"> A - Clean: Wash Vacuum, Windows, Wheels/Tires, Wax</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="bclean" class="sum" value="0" data-toggle="checkbox"> B - Clean: Same as A above <em>PLUS:</em> Shampoo Interior, Clean/Dress Interior Panels, Remove Bugs/Tar.</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="cclean" class="sum" value="109" data-toggle="checkbox"> C - Clean: Same as B above <em>PLUS:</em> Compound Polish Exterior, Clean/Dress Moldings as Needed.    </label>
</div>
</section>
<input type="text" id="total">

工作样本：https://jsfiddle.net/3veu206r/

Answer 2

使用您的代码：

见：https://msdn.microsoft.com/en-us/library/ms535126(v=vs.85).aspx

window.onload=function(){
var inputs = document.getElementsByClassName('sum'),
    total  = document.getElementById('payment-total');

 for (var i=0; i < inputs.length; i++) {
    inputs[i].onchange = function() {
        var add = this.value * (this.checked ? 1 : -1);
        total.innerHTML = parseFloat(total.innerHTML) + add
        var new_total = parseFloat(document.getElementById('input').value);
      console.log(new_total);
        document.getElementById('input').value=new_total + add
    }
  }
}

<section id="extra-features">
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="outside" class="sum" value="10" data-toggle="checkbox"> Outside Wash</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="aclean" class="sum" value="39" data-toggle="checkbox"> A - Clean: Wash Vacuum, Windows, Wheels/Tires, Wax</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="bclean" class="sum" value="0" data-toggle="checkbox"> B - Clean: Same as A above <em>PLUS:</em> Shampoo Interior, Clean/Dress Interior Panels, Remove Bugs/Tar.</label>
</div><br/>
<div class="checkbox">
<label><input type="checkbox" name="checkbox" id="cclean" class="sum" value="109" data-toggle="checkbox"> C - Clean: Same as B above <em>PLUS:</em> Compound Polish Exterior, Clean/Dress Moldings as Needed.    </label>
</div>
</section>
This is the <span> that the javascript is writing to currently:

<span id="payment-total" style="text-decoration:underline;">0</span>
<input id="input" type="text" value="0"/>

Answer 3

你必须为 jQuery 做的事情

$(total).val(parseFloat(total.innerHTML) + add);

对于javascript

total.value parseFloat(total.innerHTML) + add;