If I miss the wp_die() within the testiframe operate I get the ‘0’ appended to my output. If I put it in, the web page w/ iframe linked to it crashes

Pixeldust WordPress Developer

4 years ago

add_action('wp_ajax_ajtestiframe','testiframe');

<?php
operate testiframe() {
?>
    <head>
    <fashion>
    .aatest1 {shade:crimson;}
    </fashion>
    </head>
    <span class="aatest1">It is a check</span><br>
<?php
    echo 'That is my iframe content material<br>';
    var_dump($_GET);
}
    wp_die();
?>