许多Javascript sum字段选择并将此值输入到输入中

如果我理解正确，那么您想遍历json数据并将每个价格添加到总变量中，然后将其存储在totalprice输入中。我假设使用html标记，您将必须调整ID和类名以使其匹配。现在，当然，现在将在AJAX调用期间从数据库中动态添加每个输入的值，好像您已经弄清楚了那一部分。只要确保将JavaScript代码放在Ajax成功函数中即可。

实时预览

HTML：

<select class="product" name="product1">
<option value="" selected="selected">-</option>
<option value='20'>20</option>
</select>
<select class="product" name="product2">
    <option value="" selected="selected">-</option>
    <option value='30'>30</option>
</select>
<select class="product" name="product3">
    <option value="" selected="selected">-</option>
    <option value='40'>40</option>
</select>
<select class="product" name="product4">
    <option value="" selected="selected">-</option>
    <option value='15'>15</option>
</select>
<select class="product" name="product5">
    <option value="" selected="selected">-</option>
    <option value='22'>22</option>
</select>    

<input id="totalprice" type="text" name="totalprice" />
<input id="totaltime" type="text" name="totaltime" />

JavaScript / JQuery（置于Ajax成功函数的末尾）：

var total = 0;

//I am using this to simulate your ajax function since I don't have access to your database
$("select").on("change", function() {

  //Place the following code at the bottom of your ajax success function

  //clear out the total to
  //prevent old prices from being added to the total
  total = 0;

  $(".product").each(function() {

    //if the value is not an empty string
    if ($(this).val() !== "") {

      //add the price to the total
      total += parseInt($(this).val());

    }

  }); //end each function

  //update the total
  $("#totalprice").val(total);

}); //end on change event

更新可选解决方案：基于您的评论，我相信您会想要执行以下操作。现在请记住，您将必须更改ajax调用的url，并将datashow变量的值切换回原来的值。我必须将其更改为使用json文件来模拟您对数据库的调用。

HTML：

    <div id="products">
<select id="product1" name="product1">
    <option value="" selected="selected">-</option>
    <option value='17'>Product1</option>
</select>
<select id="product2" name="product2">
    <option value="" selected="selected">-</option>
    <option value='17'>Product1</option>
</select>
<select id="product3" name="product3">
    <option value="" selected="selected">-</option>
    <option value='17'>Product1</option>
</select>
<select id="product4" name="product4">
    <option value="" selected="selected">-</option>
    <option value='17'>Product1</option>
</select>
<select id="product5" name="product5">
    <option value="" selected="selected">-</option>
    <option value='17'>Product1</option>
</select>
        </div>

<input id="totalprice" type="text" name="totalprice" />
<input id="totaltime" type="text" name="totaltime" />

JavaScript：

$(document).ready(function() {
    $("#products select").on("change", function() {
        var id = this.value;
        $.ajax({
            url: "ajax.json",
            method: "get",
            data: "id=" + id,
            success: function(response) {               

         //initialize totalPrice to 0 if doesn't contain a value
         var totalPrice = $("#totalprice").val() !== "" ? parseInt($("#totalprice").val()): 0;

                var datashow =  response;//JSON.parse(response);
                var price1 = parseInt(datashow[0].price);
                var time1 = datashow[0].time;


                //add the total price
                $("input#totalprice").val(totalPrice + price1);

                //Do something similar for time, I don't how you plan on parsing this?
                $("input#totaltime").val(time1);


            }
        });
    });
});