CODEWITHSUNDEEP
javascriptphpajaxhtml
Jake
Jake

Reputation: 13

How to Echo Updating Variable in PHP

Thanks for coming to try and help me solve my problem!

My problem is, I would like the display a variable on my page using PHP. This variable updates every second or so. I would like this to update on the page as the variable changes. I tried using a while loop but this just continuously prints the variable. I will warn you, I am not very PHP savvy, and you're probably going to have to explain your answer to me, A LOT. Sorry I didn't include any code samples.. I didn't really think it was needed for this question. If you would like me to provide some samples, I will though. Thanks for considering answering my question! :)

Upvotes: 0

Views: 1529

Answers (3)

Teraflops
Teraflops

Reputation: 1

Someone could find it useful:

I would add loadDoc() above setInterval to fetch and display initial value (if longer than few seconds refresh time is required) , because, for example, if you want it to get refreshed every 10-15 seconds, nothing would be shown until timer finish with countdown.

var i = 1;
    // fetch and display initial value
    loadDoc();
    
    // update site content every second
    setInterval(function() {

        // run function loadDoc by timer set below
        loadDoc();

    }, 10000);

    function loadDoc() {
        var xhttp = new XMLHttpRequest();
        xhttp.onreadystatechange = function() {
            // get div with id example and update HTML
            document.getElementById("example").innerHTML = this.responseText;
        };
        xhttp.open("GET", "hello.php", true);
        xhttp.send();
    }

Anyway, my knowledge about coding is mediocre and I found this by purely experimenting. Someone should check if it is OK. I use it to successfully fetch and display server ram usage percentage.

Upvotes: 0

Andre Steudel
Andre Steudel

Reputation: 113

You try to do something which is not so easy to implement with the basics of PHP. PHP is once generated on the server side and then gives the result to the client. (your browser). If you like to change the HTML Code dynamically you should take a look at JavaScript. This will allow you to make dynamic updates without reloading the page. (e.g. a user presses a button or a timer in your case):

var i = 1;

// update site content every second
setInterval(function() {

  // get div with id example
  var myElement = document.getElementById('example');

  // count up by 1
  i++;

  // update content
  myElement.innerHTML = 'Zahl ' + i;

}, 1000);
<html>

<head>
  <meta charset="UTF-8">
  <title>JavaScript test</title>
</head>

<body>
  <div id="example">Zahl 1</div>
</body>

</html>

Now if you would like to run a PHP Script every second you need something else which is called AJAX. So for example if you would like to run hello.php every one second and set the result of it to the same div from before you need this code:

var i = 1;

// update site content every second
setInterval(function() {

  // run function loadDoc every second
  loadDoc();

}, 1000);

function loadDoc() {
  var xhttp = new XMLHttpRequest();
  xhttp.onreadystatechange = function() {
    // get div with id example and update HTML
    document.getElementById("example").innerHTML = this.responseText;
  };
  xhttp.open("GET", "hello.php", true);
  xhttp.send();
}
<html>

<head>
  <meta charset="UTF-8">
  <title>JavaScript test</title>
</head>

<body>
  <div id="example">Zahl 1</div>
</body>

</html>

Upvotes: 1

Silencer310
Silencer310

Reputation: 1090

If you want the updated variable to be shown in your browser every time, you would have to reload your client. You can do this by redirecting to the same page once the variable is updated in your PHP code.

Or you could use Ajax on your client side, which continuously sends a request to the server to get the value of the variable and then prints it in the browser.

Upvotes: 0

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