How to call a function asynchronously in PHP?

How do you call a PHP function from an onchange equals in an HTML form?

• Answer:

  You would have to do this using an AJAX request. The onchange event would trigger a Javascript function that would in turn send a request to the server, and handle the response. This requires a fair bit of back-end code for handling the AJAX, and I would recommend using an existing library for that purpose. jQuery is the one that I am familiar with, and you could handle that change event like so: <?php if(array_key_exists('mytext', $_POST)){ echo "The text you posted is "{$_POST['mytext']}""; exit; } ?> <script src="(jquery source URL here)" type="text/javascript"></script> <!-- ... --> <input type="text" id="mytext"></input> <div id="result"></div> <script type="text/javascript"> $("#mytext").change(function(){ $.post("myscript.php", {'mytext':$("#mytext").val()}, function(dat){ $("#result").HTML(dat); }); }); </script>