<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf8">
    <title>sum price</title>
  </head>
  <body>
    <table>
      <thead>
        <tr>
          <th>商品</th>
          <th>価格</th>
        </tr>
      </thead>
      <tbody>
        <tr>
          <td>デスクトップPC</td>
          <td class="price">200000</td>
        </tr>
        <tr>
          <td>モニター</td>
          <td>50000</td>
        </tr>
        <tr>
          <td>キーボード</td>
          <td>15000</td>
        </tr>
        <tr>
          <td>マウス</td>
          <td>6000</td>
        </tr>
         <tr>
          <td>プリンター</td>
          <td>40000</td>
        </tr>
      </tbody>
    </table>
  </body>
  <input type="button" value="合計">
</html>
body {
  background-color: #a3d5d3;
  font-family: 'Helvetica', 'Arial', sans-serif;
}

table,tr,th,td {
  font-size: 14px;
  list-style-type: none;
  margin: 0px auto;
  border-radius: 3px;
  border: 1px solid #000;
  padding: 5px;
  margin-bottom: 2px;
}

td {
  background: #eeeff0;
  padding-left: 15px;
}

input[type='button'] {
  display: block;
  font-size: 14px;
  margin: 20px auto 0px auto;
}
$(function(){
  $(":button").click(function(){
    // 表の金額を取得する(tdの奇数列を取得)
    var pricelist = $("table td:odd").map(function(index, val){
    //var pricelist = $("table td[class=price]").map(function(index, val){
      var price = parseInt($(val).text());
      if(price >= 0) {
        return price;
      } else {
        return null;
      }
    });
    // 価格の合計を求める
    var sum_price = 0;
    pricelist.each(function(index, val){
      sum_price = sum_price + val;
    });
  alert("合計:"+sum_price);
  });
});

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/3.4.1/jquery.min.js