AJAX Internal 500 Error in Wordpress Children-Theme

Question

I got this Ajax code on Js/Jq block (/buscador/menuLateral/menu-libros.php):

$.ajax({
  url: '<?= get_stylesheet_directory_uri(); ?>' +
    '/buscador/buscador-functions.php',
  type: 'POST',
  data: {
    sendCheckedVal: 'yes',
    tipo: 'editorial',
    valor: valor_recogido,
    archivo: this_file_id.toString()
  },
  success: function(data) {
    alert('Checked value !');
  }
});

Values on this file exists and got some value, I tried seeing it with a GET on a Stringify.

And this, must be getted in a file like this ( /buscador/buscador-functions.php) :

<?php
    if (ISSET($_POST['sendCheckedVal'])){
       echo 'hi, u reached here' ;
    }
?>

The values doesn't passes from js code file to next.

I get this error on console:

POST [WP-URL-HIDDEN-ON-PURPOSE]/themes/ChildrenNewspaper/buscador/buscador-functions.php 500 (Internal Server Error)

On right side of the line-error :

jquery.min.js:2

Someone knows how to repair this on ajax working on a wordpress theme.Thanks

Answer 1

Issue is here : alert('hi, u reached here'); . alert() is not PHP function it is javascript function. So instead of it you can use echo or return

<?php
    if (isset($_POST['sendCheckedVal'])){
       echo 'hi, u reached here';
    }
?>

Answer 2

To start you off, alert is a javascript function. In php you need to echo out values to the page;

If you want to do it with JS you need to print out js.

echo "<script type='text/javascript'>alert('hi, u reached here');</script>";

Or you can echo out the vars to the page.