javascript和html中乘法表的延迟结果

Question

 function setQuantity(upordown) { num1 = document.getElementById("firstNumber").value; num2 = document.getElementById("quantity").value; document.getElementById("Inputresult").value = num1 * num2; var quantity = document.getElementById('quantity'); if (quantity.value > 1) { if (upordown == 'up'){++document.getElementById('quantity').value;} else if (upordown == 'down'){--document.getElementById('quantity').value;} } else if (quantity.value == 1) { if (upordown == 'up'){++document.getElementById('quantity').value;} } else { document.getElementById('quantity').value=1; } }

 <input type="text" id="firstNumber" value="5" readonly/> <div class="order-option"> Quantity: <span id="quantity-field"> <input type="button" value="-" id="down" onclick="setQuantity('down');" > <input type="text" name="quantity" id="quantity" value="0"> <input type="button" value="+" id="up" onclick="setQuantity('up');"> </span> </div> <p>The Result is : <br> <input type="text" id = "Inputresult" value="" name="total" > </p>

我正在 html 中进行乘法运算，我不知道为什么结果会延迟，但我得到的语法是正确的，请帮助我如何配置这个问题。 ，请检查我在这个问题中提供的片段。 提前感谢那些帮助我配置这个问题的人。

  <input type="text" id="firstNumber" value="5" readonly/>

  <div class="order-option">
      Quantity:
      <span id="quantity-field">
          <input type="button" value="-" id="down" onclick="setQuantity('down');" >
          <input type="text" name="quantity" id="quantity" value="1" onkeyup="multiplyBy()">
          <input type="button" value="+" id="up" onclick="setQuantity('up');" onclick="multiplyBy()">
      </span>
  </div>

 <input type="text" id = "Inputresult" value="" name="total" >


<script>
    function setQuantity(upordown) {
    num1 = document.getElementById("firstNumber").value;
    num2 = document.getElementById("quantity").value;
    document.getElementById("Inputresult").value = num1 * num2;
    var quantity = document.getElementById('quantity');
    if (quantity.value > 1) {
        if (upordown == 'up'){++document.getElementById('quantity').value;}
        else if (upordown == 'down'){--document.getElementById('quantity').value;}
        }
    else if (quantity.value == 1) {
        if (upordown == 'up'){++document.getElementById('quantity').value;}
        }
    else
        {
        document.getElementById('quantity').value=1;
        }
}
</script>

Answer 1

<script>
    function setQuantity(upordown) {
   
    var quantity = document.getElementById('quantity');
    if (quantity.value > 1) {
        if (upordown == 'up'){++document.getElementById('quantity').value;}
        else if (upordown == 'down'){--document.getElementById('quantity').value;}
        }
    else if (quantity.value == 1) {
        if (upordown == 'up'){++document.getElementById('quantity').value;}
        }
    else
        {
        document.getElementById('quantity').value=1;
        }
    num1 = document.getElementById("firstNumber").value;
    num2 = document.getElementById("quantity").value;
    document.getElementById("Inputresult").value = num1 * num2;
}
</script>

像上面一样改变你的代码，

num1 = document.getElementById("firstNumber").value;
    num2 = document.getElementById("quantity").value;
    document.getElementById("Inputresult").value = num1 * num2;

上面的代码部分应该在最后一部分，因为我们需要在增量后访问文本中的值