how to make link count value ready to UPDATE mysql database.table

how to make link count value ready to UPDATE mysql database.table


For this question I use almost the same example taken from  this topic.



  1. <!DOCTYPE html>
    <html>
    <head>
        <meta charset="utf-8">
        <title>Click Counter</title>
        <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
     
     <script type="text/javascript">
    $(function(){
        $('body').on('click', 'a', function(event){
           
            var currentNumber = $('#currentNumber').text();
            $.ajax({
                method: 'POST',
                url: 'counter.php',
                data: {currentNumber : currentNumber}
            })
            .done(function(newNumber){
                $('#currentNumber').text(newNumber);
            });
        });
    });
    </script>
    </head>
    <body>
    <center>
    <br><br><br><br>
    <div id="currentNumber">0</div>
    <!--
    <button type="button">Click To Add One</button>
    -->
    <a href="https://www.jquery.com" target="_new">https://www.jquery.com</a><br>
     
    </center>
    </body>
    </html>

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For me it is unclear how to get the $_POST['currentNumber']  from the php script in a way I can send it with mysql queries to the database. 
Am I right that the jquery part here is only capable of adding a value to the post value $_POST['currentNumber'] ?
And am I right that if I want to send the same counter value to the database table I should deliver it in another way? If so, can someone explain how this data can be send to PHP to make a database entry?