为什么echo在PHP类中不起作用？

nbnkbykc 于 2023-02-15 发布在 PHP

关注(0)|答案(1)|浏览(183)

我在一个类中编写了一个名为deleteProgram()的删除函数，一切都很好，但我想添加一些javascript代码。

<?php

include_once 'db.inc.php';

class DeleteProgram extends Dbh{

    public function deleteProgram(){
        if(isset($_GET['deleteid'])){
            $id = $_GET['deleteid'];
            $sql = "DELETE FROM tblprogram WHERE id='$id';"; 

            $result = $this->connect()->query($sql);  
            header("Location: ../php/program.php");
            exit();

              
        }
    }
}

$delete = new DeleteProgram;
$delete->deleteProgram();

?>

这就是我所做的，我在deleteProgram()函数的if语句中创建了一个try/catch，然后使用echo来运行javascript代码，但是它没有显示任何内容，所以这就是卡住的地方。

<?php
echo '<script src="https://unpkg.com/sweetalert/dist/sweetalert.min.js"></script>';
include_once 'db.inc.php';

class DeleteProgram extends Dbh{

    public function deleteProgram(){
        if(isset($_GET['deleteid'])){
            $id = $_GET['deleteid'];
            $sql = "DELETE FROM tblprogram WHERE id='$id';"; 
            try{
                $result = $this->connect()->query($sql);  
                echo '<style>.swal-text{
                    text-align: center;
                }</style>';
                echo '<script>swal("Deleted Successfully!", "Program has been deleted", "success");</script>';
                header("Location: ../php/program.php");
                exit();
            }catch(PDOException $e){
                echo '<style>.swal-text{
                    text-align: center;
                }</style>';
                echo '<script>swal ( "Delete failed!" ,  "'.$e->getMessage().'" ,  "error" );</script>';
                exit();
            }
        }
    }

}

$delete = new DeleteProgram;
$delete->deleteProgram();

?>

php

来源：https://stackoverflow.com/questions/75418321/why-echo-is-not-working-inside-php-class

1条答案

按热度按时间

gg0vcinb1#

如注解中所建议，您的代码对SQL injections开放，请尝试改用parameterized prepared statements。

header()函数在页面加载之前重定向用户，因此脚本被编写但从未显示，因为新页面现在紧接着加载。
一种解决方案是使用$_SESSION，它可以像这样：
在您的DeleteProgram类PHP文件上：

# [...]
session_start();
# [...]
if(isset($_GET['deleteid'])){
    $id = $_GET['deleteid'];
    $sql = "DELETE FROM tblprogram WHERE id='$id';"; 
    try{
        $result = $this->connect()->query($sql);  
        echo '<style>.swal-text{
            text-align: center;
        }</style>';
        $_SESSION['swal'] = [
            'title' => "Deleted Successfully!",
            'message' => "Program has been deleted",
            'status' => "success"
        ];
        header("Location: ../php/program.php");
        exit();
    }catch(PDOException $e){
        # [...]
    }
}
# [...]

在../php/program.php文件中（<body>中的某个位置）：

# [...]
session_start();
# [...]
<?php if(isset($_SESSION['swal'])) {
    $title = $_SESSION['swal']['title'];
    $message = $_SESSION['swal']['message'];
    $status = $_SESSION['swal']['status'];
    echo "<script>swal($title, $message, $status);</script>";
} ?>

我也建议你不要把CSS样式放在你的代码中。它的编写位置不是很可靠。因为你的swal()函数需要你放置一个<script>标签来使用，考虑把你的<style>标签放在它旁边。*

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为什么echo在PHP类中不起作用？

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