how to write javascript code inside php

Question

i have a got a form, on clicking the submit button:

I want to do some task in the same file (db task) AND
I want the form data to be sent to test.php with the redirection

here is my code

    <?php
    if(isset($_POST['btn'])){
        //do some task
    ?>
    <script type="text/javascript">
        var e = document.getElementById('testForm'); e.action='test.php'; e.submit();</script>
    <?php
    }
    ?>
<form name="testForm" id="testForm"  method="POST"  >
    <input type="submit" name="btn" value="submit" autofocus  onclick="return true;"/>
 </form>

but not able to submit the form, if i call the javascript code on onClick, it works.what is the problem in this code, Is there any work around for this

Pretty logical, your javascript runs at the moment it is outputted in the browser and your form is printed ... after that. You should enclose your code in a window.onload event listener so that it is only executed after the page load completion. — yent
– yent, Commented May 15, 2012 at 7:42

keto23 · Accepted Answer · 2012-05-15 07:45:29Z

83

Just echo the javascript out inside the if function

 <form name="testForm" id="testForm"  method="POST"  >
     <input type="submit" name="btn" value="submit" autofocus  onclick="return true;"/>
 </form>
 <?php
    if(isset($_POST['btn'])){
        echo "
            <script type=\"text/javascript\">
            var e = document.getElementById('testForm'); e.action='test.php'; e.submit();
            </script>
        ";
     }
  ?>

answered May 15, 2012 at 7:45

keto23

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1 Comment

chiborg Over a year ago

Please note the the solution here is not generating the JavaScript code with PHP but the fact that the PHP block comes after the form tags which means the DOM element 'testForm' is initialized when the JavaScript is executed.

Peter Dvukhrechensky · Accepted Answer · 2019-12-28 07:45:37Z

12

Lately I've come across yet another way of putting JS code inside PHP code. It involves Heredoc PHP syntax. I hope it'll be helpful for someone.

<?php
$script = <<< JS

$(function() {
   // js code goes here
});

JS;
?>

After closing the heredoc construction the $script variable contains your JS code that can be used like this:

<script><?= $script ?></script>

The profit of using this way is that modern IDEs recognize JS code inside Heredoc and highlight it correctly unlike using strings. And you're still able to use PHP variables inside of JS code.

answered Dec 28, 2019 at 7:45

Peter Dvukhrechensky

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Comments

nischayn22 · Accepted Answer · 2012-05-15 07:58:42Z

6

You can put up all your JS like this, so it doesn't execute before your HTML is ready

$(document).ready(function() {
   // some code here
 });

Remember this is jQuery so include it in the head section. Also see Why you should use jQuery and not onload

edited May 15, 2012 at 7:58

answered May 15, 2012 at 7:50

nischayn22

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Comments

chiborg · Accepted Answer · 2012-05-15 07:42:02Z

5

At the time the script is executed, the button does not exist because the DOM is not fully loaded. The easiest solution would be to put the script block after the form.

Another solution would be to capture the window.onload event or use the jQuery library (overkill if you only have this one JavaScript).

answered May 15, 2012 at 7:42

chiborg

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Comments

James Risner · Accepted Answer · 2022-10-30 23:43:57Z

0

You can use PHP echo and then put your JavaScript code:

<?php
      echo "
            <script>
              alert('Hellow World');
            </script>
        "; 
?>

edited Oct 30, 2022 at 23:43

James Risner

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answered Oct 26, 2022 at 11:22

zabbir hossain

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