javascript alert box not showing on php after header redirect

Question

I am trying to display an alert box before redirecting to another page, here is my code, when I remove the header function it works properly but when it is here it will just redirect to the page without showing the alert box.

<html>
    <body>
        <?php
        include("dbconfig.php");

        $tempid = mysqli_real_escape_string($dbconfig, $_POST['tempid']);

        $sql_query = "DELETE FROM Visits
    WHERE visitid = '$tempid'";
        $result = Mysqli_query($dbconfig, $sql_query);
        if ($result) {

            echo '<script language="javascript">';
            echo 'alert("visit deleted successfully")';
            echo '</script>';

            header("location:../SearchCountry/search.php");
        }
        ?>
    </body>
</html>

`language="javascript"` is that from 2002? http://stackoverflow.com/questions/2267476/html-script-tag-type-or-language-or-omit-both — Roko C. Buljan, May 01 '16 at 14:24
It is showing, but the insta-redirect is killing all the fun — Alex Lomia, May 01 '16 at 14:24
PHP is being executed on server side.. And once it is rendered in browser, ` — Rayon, May 01 '16 at 14:24
i see, so using a javascript code so that it wait for the "ok" button to be pressed then it redirects should do it, however using javascript in php is kind of annoying — Xtrem fabz, May 01 '16 at 14:27
Php executes first and javascript executes later so adjust your code accordingly — wui, May 01 '16 at 14:35

score 6 · Answer 1 · answered May 01 '16 at 14:34

PHP is executed at the server side. It renders HTML/JS/CSS and sends it to the web browser, the web browser then parses and executes the JavaScript (In your case, show the alert dialog.)

However, once you call

header ("location:../SearchCountry/search.php");

The browser will be informed to redirect the user to ../SearchCountry/search.php immediately, without a chance to parse and execute the JavaScript. That's why the dialog will not show up.

Solution: redirect your user to another page with JavaScript instead of PHP.

 <html>
 <?php
 include("dbconfig.php");

 $tempid = mysqli_real_escape_string($dbconfig,$_POST['tempid']);

$sql_query = "DELETE FROM Visits
WHERE visitid = '$tempid'";
$result = Mysqli_query($dbconfig,$sql_query);
if($result){
    echo '<script language="javascript">';
    echo 'alert("visit deleted successfully");\n';
    echo 'window.location.href="../SearchCountry/search.php"'; //Redirects the user with JavaScript
    echo '</script>';
    die(); //Stops PHP from further execution
}
 ?>
</body>
</html>

score 5 · Accepted Answer · answered May 01 '16 at 14:25

5

echo "<script>
alert('visit deleted successfully');
window.location.href='SearchCountry/search.php';
</script>";

and get rid of redirect line below.

You were mixing up two different worlds.

answered May 01 '16 at 14:25

Naresh Kumar

561
2
15

big up to you my friend, it says i have to wait 7 mins to mark as answer haha since im a noob here i have no idea why, by chance do you have any idea how i could make that alert box use two buttons like "ok" and "cancel"? – Xtrem fabz May 01 '16 at 14:30
1

@Xtremfabz use confirm instead of alert =) – Naresh Kumar May 01 '16 at 14:36
1

you can use if else, as the confirm function returns true or false you can use it to control yes or no `var answer = confirm("visit deleted successfully") if (answer){ // if user click on yes window.location.href='SearchCountry/search.php'; } else{ //if user click on no document.write("sorry"); }` – Naresh Kumar May 01 '16 at 15:02
Answers with explanations are always good, too. (See Kevin's answer below, for a fuller description of what is happening.) – HoldOffHunger Aug 28 '18 at 17:15

javascript alert box not showing on php after header redirect

2 Answers2