How to call PHP function from Javascript (ideally without AJAX)

Question

Don't really know AJAX that well.. Here is the issue.

I am reading a database within the PHP function that populate some global variables, I can access the variables ok, but I need the php function to be called regularly.

<?php

function thatIwant()
{
  //read database
 return 10;
}

echo("
<script>

function refreshDiv()
    {
     //// this is where I need to call the above function.
     var refresher = setTimeout('refreshDiv()', 2000);
    }
</script>
");
?>

You must use AJAX. Client-side code can't call server-side code except through an HTTP request. — 4castle, Apr 16 '17 at 20:22
_"Don't really know AJAX that well."_ [That is fairly easily remedied.](https://learn.jquery.com/ajax/) — Alex Howansky, Apr 16 '17 at 20:22
Also, calling `setTimeout` with a string parameter is bad practice. Use a function reference: `var refresher = setTimout(refreshDiv, 2000);` — 4castle, Apr 16 '17 at 20:31

furkle · Answer 1 · 2017-04-16T20:44:42.193

1

You can't call a PHP function regularly from Javascript without the use of an XmlHttpRequest. PHP is executed when the page is first requested. With an XHR, you could do the following:

function refreshDiv() {
    setTimeout(function() {
        var xhr = new XmlHttpRequest();
        xhttp.onreadystatechange = function() {
            if (this.readyState === 4 && this.status === 200) {
                document.getElementById("refreshDiv").innerHTML = 
xhr.responseText;
            }
        };

        xhttp.open("GET", "yourPHPEndpoint.php", true);
        xhttp.send();
    }, 1000);
}

This would allow you to query your PHP file continuously, and update the contents of the div with the result of the query. This can also be done through jQuery with $.ajax or $.get.

edited Apr 16 '17 at 20:44

answered Apr 16 '17 at 20:24

furkle

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Thanks for this - would the above code just be used like any other function in JS. – Sam Brown Apr 16 '17 at 20:30
@SamBrown Just add it in a ` – furkle Apr 16 '17 at 20:32
How can I use the above code in my function refreshDiv() – Sam Brown Apr 16 '17 at 20:36
Also what is yourDiv for in code – Sam Brown Apr 16 '17 at 20:37
@SamBrown You don't need to, but you can just copy it into `refreshDiv`. Make sure you only call it once, though, because it's creating a timeout that will fire on its own once a second. – furkle Apr 16 '17 at 20:37
@SamBrown Your question is a duplicate. You will find much better answers on the duplicate post. – 4castle Apr 16 '17 at 20:40
I have been looking - not getting anywhere really. – Sam Brown Apr 16 '17 at 20:43
@SamBrown I've updated the code for the `refreshDiv` function. – furkle Apr 16 '17 at 20:44
A shame no more up votes here. First because indeed the availability of the XmlHttpRequest() has made it possible to do something that previously could only be done except as an http request from an anchor tag, and second because of all the negative "you can't do that without AJAX" answers to similar questions, peppered throughout the internet. A hearty thanks to @furkle for the confirmation, as I've been doing this for a while and was worried I was missing a serious 'why not" restriction. – Randy May 28 '19 at 19:20
Very bad example, not the right variable names and "XmlHttpRequest" is also wrong written. Better example: https://stackoverflow.com/a/4033310/8283938 – Falke Design Sep 08 '19 at 20:51

How to call PHP function from Javascript (ideally without AJAX)

1 Answers1