Question

我初始化了$_SESSION variable = 1，我希望在点击链接时increment/decrements其值。链接将重新加载页面，然后回显$_SESSION的值。我使用header()给了一个提示，但我仍然无法弄清楚如何。

<?php  
        if (isset($_SESSION['count'])) {
            $count = $_SESSION['count'];
        } else {
            $count = '';
        }
    ?>
    <a href="index.php?inc=TRUE">Increment</a>
    <a href="index.php?dec=TRUE">Decrement</a>
    <?php if (isset($_SESSION['count'])): ?>
        <?php echo $count ?>
    <?php endif ?>

Answer 1

header("Location: index.php")是一个php重定向。在这种情况下，如果上面的代码已经在 index.php 文件中，则无需重定向用户。

<?php
    session_start();
    if(!isset($_SESSION['count']) { // first time opening the page
        $_SESSION['count'] = 0; // initializing the counter
    } else { // counter already have a value
        if(isset($_GET['inc'])) { // increasing
            echo ++$_SESSION['count']; // no need for extra variable (preincrement to echo immediately)
        }
        if(isset($_GET['dec'])) { // decreasing
            echo --$_SESSION['count']; // no need for extra variable (predecrement to echo immediately)
        }
    } 
?>
<a href="index.php?inc=TRUE">Increment</a>
<a href="index.php?dec=TRUE">Decrement</a>

Answer 2

<?php 
    session_start();

    if(!isset($_SESSION['count'])
        $_SESSION['count'] = 0;

    $counter = $_SESSION['count']; 
    $counter = (int)$counter;

    if (isset($_GET['inc'])==TRUE) { 
        $counter++;
        $_SESSION['count'] = $counter; 
        header("Location: index.php"); 
    }

    if (isset($_GET['dec'])==TRUE) { 
        $counter--;
        $_SESSION['count'] = $counter; 
        header("Location: index.php"); 
    }
?>

此外，您可能需要将$ counter转换为int ..

单击按钮时递增/递减$ _SESSION变量。提示标题（）

2 个答案: