Execute PHP function with onclick

I am searching for a simple solution to call a PHP function only when a-tag is clicked.

PHP:

function removeday() { ... }

HTML:

<a href="" onclick="removeday()" class="deletebtn">Delete</a>

UPDATE: the html and PHP code are in the same PHP file

Answers:

Answer

First, understand that you have three languages working together:

  • PHP: It only runs by the server and responds to requests like clicking on a link (GET) or submitting a form (POST).

  • HTML & JavaScript: It only runs in someone's browser (excluding NodeJS).

I'm assuming your file looks something like:

<!DOCTYPE HTML>
<html>
<?php
  function runMyFunction() {
    echo 'I just ran a php function';
  }

  if (isset($_GET['hello'])) {
    runMyFunction();
  }
?>

Hello there!
<a href='index.php?hello=true'>Run PHP Function</a>
</html>

Because PHP only responds to requests (GET, POST, PUT, PATCH, and DELETE via $_REQUEST), this is how you have to run a PHP function even though they're in the same file. This gives you a level of security, "Should I run this script for this user or not?".

If you don't want to refresh the page, you can make a request to PHP without refreshing via a method called Asynchronous JavaScript and XML (AJAX).

That is something you can look up on YouTube though. Just search "jquery ajax"

I recommend Laravel to anyone new to start off right: http://laravel.com/

Answer

In javascript, make an ajax function,

function myAjax() {
      $.ajax({
           type: "POST",
           url: 'your_url/ajax.php',
           data:{action:'call_this'},
           success:function(html) {
             alert(html);
           }

      });
 }

Then call from html,

<a href="" onclick="myAjax()" class="deletebtn">Delete</a>

And in your ajax.php,

if($_POST['action'] == 'call_this') {
  // call removeday() here
}
Answer

You will have to do this via AJAX. I HEAVILY reccommend you use jQuery to make this easier for you....

$("#idOfElement").on('click', function(){

    $.ajax({
       url: 'pathToPhpFile.php',
       dataType: 'json',
       success: function(data){
            //data returned from php
       }
    });
)};

http://api.jquery.com/jQuery.ajax/

Answer

It can be done and with rather simple php if this is your button

<input type="submit" name="submit>

and this is your php code

if(isset($_POST["submit"])) { php code here }

the code get's called when submit get's posted which happens when the button is clicked.

Answer

Try to do something like this:

<!--Include jQuery-->
<script type="text/javascript" src="jquery.min.js"></script> 

<script type="text/javascript"> 
function doSomething() { 
    $.get("somepage.php"); 
    return false; 
} 
</script>

<a href="#" onclick="doSomething();">Click Me!</a>
Answer

Solution without page reload

<?php
  function removeday() { echo 'Day removed'; }

  if (isset($_GET['remove'])) { return removeday(); }
?>


<!DOCTYPE html><html><title>Days</title><body>

  <a href="" onclick="removeday(event)" class="deletebtn">Delete</a>

  <script>
  async function removeday(e) {
    e.preventDefault(); 
    document.body.innerHTML+= '<br>'+ await(await fetch('?remove=1')).text();
  }
  </script>

</body></html>
Answer

This is the easiest possible way. If form is posted via post, do php function. Note that if you want to perform function asynchronously (without the need to reload the page), then you'll need AJAX.

<form method="post">
    <button name="test">test</button>
</form>

    <?php
    if(isset($_POST['test'])){
      //do php stuff  
    }
    ?>
Answer

Try this it will work fine.

<script>
function echoHello(){
 alert("<?PHP hello(); ?>");
 }
</script>

<?PHP
FUNCTION hello(){
 echo "Call php function on onclick event.";
 }

?>

<button onclick="echoHello()">Say Hello</button>
Answer

Here´s an alternative with AJAX but no jQuery, just regular JavaScript:

Add this to first/main php page, where you want to call the action from, but change it from a potential a tag (hyperlink) to a button element, so it does not get clicked by any bots or malicious apps (or whatever).

<head>
<script>
  // function invoking ajax with pure javascript, no jquery required.
  function myFunction(value_myfunction) {
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function() {
      if (this.readyState == 4 && this.status == 200) {
        document.getElementById("results").innerHTML += this.responseText; 
        // note '+=', adds result to the existing paragraph, remove the '+' to replace.
      }
    };
    xmlhttp.open("GET", "ajax-php-page.php?sendValue=" + value_myfunction, true);
    xmlhttp.send();
  }

</script>
</head>

<body>

  <?php $sendingValue = "thevalue"; // value to send to ajax php page. ?> 

  <!-- using button instead of hyperlink (a) -->
  <button type="button" onclick="value_myfunction('<?php echo $sendingValue; ?>');">Click to send value</button>

  <h4>Responses from ajax-php-page.php:</h4>
  <p id="results"></p> <!-- the ajax javascript enters returned GET values here -->

</body>

When the button is clicked, onclick uses the the head´s javascript function to send $sendingValue via ajax to another php-page, like many examples before this one. The other page, ajax-php-page.php, checks for the GET value and returns with print_r:

<?php

  $incoming = $_GET['sendValue'];

  if( isset( $incoming ) ) {
    print_r("ajax-php-page.php recieved this: " . "$incoming" . "<br>");
  } else {
    print_r("The request didn´t pass correctly through the GET...");
  }

?>

The response from print_r is then returned and displayed with

document.getElementById("results").innerHTML += this.responseText;

The += populates and adds to existing html elements, removing the + just updates and replaces the existing contents of the html p element "results".

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