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Php – AJAX Call Returning "Undefined array key"

I cannot get my AJAX to work. Any help would be appreciated as I have spent hours on this with no avail. I am using test-data until I stop getting an error:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>

My AJAX:

            $.ajax({
                type: 'POST',
                url: 'addsMeal.php',
                dataType:'json', 
                data: ({name: 'Emma'}),
                success: function () {
                    console.log("Sent data to addsMeal PHP file successfully.");
                }
            });

addsMeal.php:


<?php
    // topFields, newIngredient
    $name = $_POST['name'];
    echo($name);
?>

The error is:
Warning: Undefined array key "name" in C:xampphtdocsGroceryListGeneratorPagesaddsMeal.php on line 3.

The console logs the data was sent successfully…

Tags:

2

Answers


  1. 0

    Try modifying your PHP code to check if the ‘name’ key exists before accessing it:

    <?php
    if(isset($_POST['name'])) {
        $name = $_POST['name'];
        echo $name;
    } else {
        echo "No name parameter received.";
    }
?>

    This will prevent the warning and handle cases where the ‘name’ parameter is not received properly.

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  2. 0

    As a brief and quickly written example of a single page jQuery/PHP app perhaps the following might help clarify some of the points made above.

    <?php
    error_reporting( E_ALL );
    
    # logic test - only process ajax request if it is a POST request 
    # testing for key POST variables that you MUST have to contine 
    # makes sense.
    if( $_SERVER['REQUEST_METHOD']=='POST' && isset(
        $_POST['name'],
        $_POST['colour'],
        $_POST['music'],
        $_POST['car']
    )){
    
        # ensure that no HTML before output 
        # is included in response
        ob_clean();
        
        
        # process AJAX request... do something interesting & send a response
        vprintf('The computer says: "<span>%s</span>" drove a "<span>%s %s</span>" 
        way too fast whilst listening to "<span>%s</span>" full blast', $_POST );
        
        /*
            update db, read from db, create images etc etc
        */
        
        # exit/die - ensure the whole HTML page 
        # does not become part of the response
        exit();
    }
?>
<!DOCTYPE html>
<html lang='en'>
    <head>
        <meta charset='utf-8' />
        <title>Single page basic jQuery/Ajax to PHP script.</title>
        <script src='//code.jquery.com/jquery-latest.js'></script>
        <style>
            div span{ color:red }
        </style>
    </head>
    <body>
        <div></div>
        <script>
            $.ajax({
                type:'POST',
                /* 
                    adding the `dataType:"json"` means you expect JSON
                    - which is fine but omitted here as response is
                    HTML
                */
                url:location.href,
                data: ({
                    'name':'Emma',
                    'colour':'bright red',
                    'car':'Jaguar XKR',
                    'music':'The Dead Kennedys'
                }),
                success:function(r) {
                    document.querySelector('div').innerHTML=r;
                }
            });
        </script>
    </body>
</html>

    Which outputs a nonsense string:

    The computer says: "Emma" drove a "bright red Jaguar XKR" way too fast
    whilst listening to "The Dead Kennedys" full blast

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