我根本沒有做任何javascript，我試圖從選擇類中總結2個值。我可以將它們都顯示出來，但沒有總結出來。誰能解釋為什么我得到“[object HTMLParagraphElement]”作為答案？謝謝function GetSelectedValue1() { const f = document.getElementById("value1"); const result = f.options[f.selectedIndex].value; document.getElementById("result").innerHTML = result; const e = document.getElementById("value2"); const result2 = e.options[e.selectedIndex].value; document.getElementById("result2").innerHTML = result2; const g = +result + result2; document.getElementById("result3").innerHTML = result3;}HTML（它很笨拙，只是在測試）： <div class="container vertical-center d-flex justify-content-center" id="stock-box"> <ul class="list-group"> <li class="list-group-item d-flex justify-content-between align-items-center list-group-item-action"> <b>Order:</b> <div class="btn-group"> <select class="custom-select" name="stock-box-margin40" id="value1"> <option selected>Choose Quantity</option> <option value="1">1</option> <option value="2">2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> <option value="6">6</option> <option value="7">7</option> <option value="8">8</option> <option value="9">9</option> <option value="10">10</option> </select> <p id="result">United State</p> <button type="button" onclick="GetSelectedValue1()">Get Selected Value</button> </div> </li>
如何使用 javascript 對 Select 類中的 2 個變量求和？
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2022-05-26 16:32:53
