function not defined php-js

Question

I have this piece of code into my php file:

<?php
if(isset($_POST['submit'])){
     if($_POST['email'] != ''){
           $email = $_POST['email'];
           $query = "INSERT INTO user(email) VALUES('". $email . "')";
           $stmt = $db ->query($query);
           if($stmt){
                 echo "<script>displayPopup('success')</script>";
           }else{
                echo "";
           }
      }
  }
?>

My JS file is included before the closing tag and it's well charged. But I have error saying the function displayPopup is not defined

Any idea ? :(

try moving your displayPopup function to the top of the page just before the </head> tag. — William Cross
– William Cross, Commented Apr 28, 2017 at 11:42
If you know jQuery check the $(document).ready(); function — JustOnUnderMillions
– JustOnUnderMillions, Commented Apr 28, 2017 at 11:42
The JS file needs to be included before the call to displayPopup — brettwhiteman
– brettwhiteman, Commented Apr 28, 2017 at 11:45
Show where the function is defined. You also are open to SQL injections. — chris85
– chris85, Commented Apr 28, 2017 at 11:51

William Cross · Accepted Answer · 2017-04-28 11:48:25Z

1

The main problem as far as I can tell is that the displayPopup function is being defined at the end of your document.

PHP being server-side and JS being client side, the conditions for echo'ing your script occur before the javascript is loaded/read.

This means that at the moment of that script being executed, the "displayPopup" function does not, in fact, exist.

Quickest way to test is to add the following code just before the end of your < /head> tag:

<script type="text/javascript">
    function displayPopup(msg){
        alert(msg);
    }
</script>

You can always obviously replace that function with whatever your actual displayPopup function is. An alternative to this is to use Ajax to submit your forms for a more seamless experience but the above should fix your issue.

I hope this helps!

answered Apr 28, 2017 at 11:48

William Cross

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1 Comment

William Cross Over a year ago

alternatively you can just add the complete js file before the end of the </head> tag instead of putting it at the end of the document, but this may impact page load times

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