샐렉트 값에 따라 결과값이 틀리게 나오게

가장 먼저 샐렉트메뉴에서 304 또는 316L을 선택하게 되는데요

304를 선택할시에는 그냥 값이 나오면 되는데

316L을 선택했을때는 두배(x2)값으로 나오게 하려면 어떻게 해야할까요?ㅜㅜ

고수님들의 도움 부탁드립니다.

감사합니다.

<?php
include './_common.php';
include_once G5_THEME_PATH.'/head.php';
?>
<section class="content_wrap">
  <div class="txtCon">
    <div class="non-payment_area">
       <div class="content-box"> 
          <table class="tbl-stat" id="tbl-rank">
            <caption>
            </caption>
            <colgroup>
            
            <col style="width: 33.33333%;">
                
            </colgroup>
            <thead>
             
               <tr>
                <th scope="col">
<div style="margin:10px 0">
                        <select class="form-select unit" required><!--여기서 선택을 합니다.-->
                            <option value="">강종 선택</option>
                            <option value="304">304</option>
                            <option value="316l">316L</option>
                        </select>
                    </div>
                    
<div style="margin:10px 0">
  <label for="price" style="display:block;margin-bottom:5px">외경</label>
  <input type="text" id="price" style="outline: 1px solid #000;" placeholder="입력" onkeyup="calculateResult()">
</div>
<div style="margin:10px 0">
  <label for="price1" style="display:block;margin-bottom:5px">두께</label>
  <input type="text" id="price1" style="outline: 1px solid #000;" placeholder="입력" onkeyup="calculateResult()">
</div>
<div style="margin:10px 0">
  <label for="result" style="display:block;margin-bottom:5px">외경-두께</label>
  <input type="text" id="result" style="outline: 1px solid #000;" placeholder="자동계산" readonly>
</div>
<div style="margin:10px 0">
  <label for="result1" style="display:block;margin-bottom:5px">(외경-두께)-두께</label>
  <input type="text" id="result1" style="outline: 1px solid #000;" placeholder="자동계산" readonly>
</div>
<div style="margin:10px 0">
  <label for="result2" style="display:block;margin-bottom:5px">(외경-두께)-두께*0.02491</label>
  <input type="text" id="result2" style="outline: 1px solid #000;" placeholder="자동계산" readonly>
</div>
<div style="margin:10px 0">
  <label for="price2" style="display:block;margin-bottom:5px">구조율</label>
  <input type="text" id="price2" style="outline: 1px solid #000;" placeholder="입력" onkeyup="calculateResult()">
</div>
<div style="margin:10px 0">
  <label for="result3" style="display:block;margin-bottom:5px">산출값</label>
  <input type="text" id="result3" style="outline: 1px solid #000;" placeholder="자동계산" readonly>
</div>

<script>
  function calculateResult() {
    let price = document.getElementById('price').value;
    let price1 = document.getElementById('price1').value; 
    let result = price - price1; 
    let result1 = (price - price1) * price1;
    let result2 = (price - price1) * price1 * 0.02491; 
    let price2 = document.getElementById('price2').value; 
    let result3 = (price - price1) * price1 * 0.02491 * price2;   
    document.getElementById('result').value = result;
    document.getElementById('result1').value = result1;
    document.getElementById('result2').value = result2; 
    document.getElementById('result3').value = result3;     <!--여기가 최종 결과값입니다.-->
  }
</script></th>
              </tr>    
            </thead>
         
          </table>
        </div>
    </div>
  </div>
</section>
<!--content_wrap-->

<?php
include_once(G5_THEME_PATH . '/tail.php');
?>