我是PHP的新手，当单选按钮被单击时，我尝试在文本框中显示一个值（$total_discount）。但每当我的单选按钮被点击时，它只输出一个文本“未定义”。这是我的代码。

<代码><；脚本类型="；文本/JavaScript"；>；函数insertDiscount（getDiscount）{document.getElementById（"；折扣"；）。值=获取折扣；}<；/脚本>；<；？PHP$数量=$_后["；数量"；]；$折扣_a=0.10；$_折扣价；$_折扣总额；if（isset（$item_价格））{$折扣_价格=$物料_价格X$折扣_A；_总折扣金额=_价格折扣额*数量。}？>；<；输入类型="；文本"；name="；折扣"；ID="；折扣"；值="；"；>；<；输入类型="；单选"；name="；折扣"；ID="；折扣_A"；onclick="；InsertDiscount（' '。$总_折扣）；"；>；<；标签="；折扣_A"；>；10%折扣<；/标签>；

顺晟科技：

<代码><；输入类型="；电台"；name="；折扣"；ID="；折扣_A"；onclick="；InsertDiscount（' '。$总_折扣）；"；>；

• 要输出$total_discount的值，您需要insertDiscount()，它将回显该值

所以你的最终结果会像这样。

<?php if(isset($total_discount)): ?>
    <input type="radio" name="discounts" id="discount_A" onclick="insertDiscount(<?=$total_discount?>);">
<?php else: ?>
    <!-- First you can assign $total_discount variable value then pass it -->
    <?php $total_discount = 10; ?>
    <input type="radio" name="discounts" id="discount_A" onclick="insertDiscount(<?=$total_discount?>);">
<?php endif ?>

• 输出未定义，因为onclick="insertDiscount(<?php echo($total_discount); ?>)"变量未定义。
• 首先可以检查onclick="insertDiscount(<?php echo($total_discount); ?>)"不为空。
• 如果$total_discount不为空，则可以在JavaScript函数$total_discount中传递$Total_折扣
• 如果<script type="text/javascript"> function insertDiscount(getDiscount) { document.getElementById("discount").value = getDiscount; } </script> <?php $quantity = $_POST["quantity"]; $discount_a = 0.10; $discounted_price; $total_discount; if(isset($item_price)){ $discounted_price = $item_price * $discount_a; $total_discount = $discounted_price * $quantity; } ?> <input type="text" name="discount" id="discount" value=""> <input type="radio" name="discounts" id="discount_A" onclick="insertDiscount(''.$total_discount);"> <label for="discount_A">10% Discount</label> 为NULL或未定义，则可以分配<script type="text/javascript"> function insertDiscount(getDiscount) { document.getElementById("discount").value = getDiscount; } </script> <?php $quantity = $_POST["quantity"]; $discount_a = 0.10; $discounted_price; $total_discount; if(isset($item_price)){ $discounted_price = $item_price * $discount_a; $total_discount = $discounted_price * $quantity; } ?> <input type="text" name="discount" id="discount" value=""> <input type="radio" name="discounts" id="discount_A" onclick="insertDiscount(''.$total_discount);"> <label for="discount_A">10% Discount</label> 变量值，并传入JavaScript函数$total_discount

  PHP不会呈现变量<script type="text/javascript"> function insertDiscount(getDiscount) { document.getElementById("discount").value = getDiscount; } </script> <?php $quantity = $_POST["quantity"]; $discount_a = 0.10; $discounted_price; $total_discount; if(isset($item_price)){ $discounted_price = $item_price * $discount_a; $total_discount = $discounted_price * $quantity; } ?> <input type="text" name="discount" id="discount" value=""> <input type="radio" name="discounts" id="discount_A" onclick="insertDiscount(''.$total_discount);"> <label for="discount_A">10% Discount</label> 的值。

  查纳吉

  $total_discount

  向

  onclick="insertDiscount(''.$total_discount);"

  以达到预期的结果。