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PHP-如何在提交按钮单击时增加值

作者：互联网

我想知道每次发布元素时如何增加元素.

我必须使用for循环进行自动递增,但是我做错了.因此,任何建议或指导都会很棒.

这是我尝试做的方式：

谢谢

<?php

$id=0;    
if (isset($_POST['submit'])) {
  $do = $_POST['prodCode'];
  $di = count($do);

  while ($di > $id) { 
    $id++;
    echo $id;
  }
}
?>

<!DOCTYPE HTML>
<html>
  <head>
    <title>Session test</title>
  </head>
  <body>
    <div class="holder">
      <div class="im">
        <img src="session-test/images/bestorange-juice.jpg" />
        <p>bestorange-juice</p>
        <form method="post" action="sessiontest.php">
          <input type="hidden" id="prodCode" name="prodCode" value="f102" />
          <input type="hidden" id="prodPrice" name="prodPrice" value="25" />
          <!--<input type="text" id="prodQty" name="prodQty" value="1" size="1"/>-->
          <input type="submit" value="send value" name="submit" id="submit" />
        </form>
      </div>
      <div class="im">
        <img src="session-test/images/milkshake-juice.jpg" />
        <p>bestorange-juice</p>
        <form method="post" action="sessiontest.php">
          <input type="hidden" id="prodCode" name="prodCode" value="W122" />
          <input type="hidden" id="prodPrice" name="prodPrice" value="1" />
          <!--<input type="text" id="prodQty" name="prodQty" value="1" size="1"/>-->
          <input type="submit" value="send value" name="submit" id="submit" />
        </form>
      </div>
    </div>
  </body>
</html>

解决方法:

尝试下面的代码,计数存储在会话中,但是对于现实生活中的应用,您应该使用数据库,并且还应该从数据库中获取产品：

<?php

// initialize counts for f102 and W122 products
if (!isset($_SESSION['count_f102']) {
   $_SESSION['count_f102'] = 0;
}
if (!isset($_SESSION['count_W122']) {
   $_SESSION['count_f102'] = 0;
}

if (isset($_POST['submit'])) {
  $do = $_POST['prodCode'];
  // increment count for product which was submitted
  $_SESSION['count_'.$do] = 1+ (int) $_SESSION['count_'.$do];
}
?>

<!DOCTYPE HTML>
<html>
  <head>
    <title>Session test</title>
  </head>
  <body>
    <div class="holder">
      <div class="im">
        <img src="session-test/images/bestorange-juice.jpg" />
        <p>bestorange-juice</p>
        <form method="post" action="sessiontest.php">
          <input type="hidden" id="prodCode" name="prodCode" value="f102" />
          <input type="hidden" id="prodPrice" name="prodPrice" value="25" />
          <input type="text" id="prodQty" name="prodQty" value="<?php $_SESSION['count_f102'] ?>" size="1" readonly="readonly" />
          <input type="submit" value="send value" name="submit" id="submit" />
        </form>
      </div>
      <div class="im">
        <img src="session-test/images/milkshake-juice.jpg" />
        <p>bestorange-juice</p>
        <form method="post" action="sessiontest.php">
          <input type="hidden" id="prodCode" name="prodCode" value="W122" />
          <input type="hidden" id="prodPrice" name="prodPrice" value="1" />
          <input type="text" id="prodQty" name="prodQty" value="<?php $_SESSION['count_W122'] ?>" size="1" readonly="readonly" />
          <input type="submit" value="send value" name="submit" id="submit" />
        </form>
      </div>
    </div>
  </body>
</html>

标签：auto-increment,php
来源： https://codeday.me/bug/20191119/2037834.html