PHP isset variable than jquery and javascript should work

Question

I want to know if my php variable does not exists, then I want to execute my javascript.

For example-

<?php
if(!isset($_REQUEST['myVar'])){
   ?>
   <script>
   alert('variable not exist');
   </script>
   <?php
}
?>

Is this right way to use javascript code in php extension file

But why are you doing this? Mixing the server-side and client-side code? O.o — Sahil Mittal
– Sahil Mittal, Commented Jun 27, 2014 at 7:15
acctuly i tried , i just want to kow is that fine for my script to use javascript inside my php file , is there any alternate ? and thank you both — user3755020
– user3755020, Commented Jun 27, 2014 at 7:16

Jeetendra Chauhan · Accepted Answer · 2014-06-27 08:02:04Z

1

I know all other answers solve your issue but i prefer it to do this way

<script>
    <?php 
        $isset = !isset($_POST['myVar']) ? 'true' : 'false';
        echo "var isset = $isset;";
    ?>
    if(isset) {
      alert('variable not exist');
    }
</script>

when php render your page it will give this output

<script>
    var isset = true;       
    if(isset) {
      alert('variable not exist');
    }
</script>

edited Jun 27, 2014 at 8:02

answered Jun 27, 2014 at 7:33

Jeetendra Chauhan

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7 Comments

Pratik Joshi Over a year ago

How can u access => isset variable WITHOUT $ in javascript?

Jeetendra Chauhan Over a year ago

downvoter i think nothing wrong in this snippet,this is more readable then other isn't it

Jeetendra Chauhan Over a year ago

@PratikJoshi isset is javascript variable while $isset is php variable,i think you didn't see my snippet properly

Pratik Joshi Over a year ago

Parse error: syntax error, unexpected T_ECHO in /var/www/html/sample123.php on line 4. This 4th line gives error => echo "var isset = $isset;";

Jeetendra Chauhan Over a year ago

change that line to echo "var isset = ".$isset.";";

|

Vaidas · Accepted Answer · 2014-06-27 13:27:12Z

0

Do it like this and it will work:

if (!isset($_REQUEST['myVar'])) {

    echo "<script>alert('variable not exist');</script>";
}

edited Jun 27, 2014 at 13:27

Vaidas

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answered Jun 27, 2014 at 7:28

Sankalp Srivastava

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6 Comments

user3755020 Over a year ago

is this a professional way to execute php and javascript code ? and thanks for reply

Sankalp Srivastava Over a year ago

no this is not the professional way. its a simple hack. I you want a professional way you have the save a cookie through PHP and then you have to check through jquery if the cookie exist or not or the second solution given by Rakesh(below). The error you were making was you were closing echo inside your alert script alert(**'**variable not exist**'**);

user3755020 Over a year ago

thanks for explanation, so you mean , if i need to mix php with javascript than i have to use cookies over there ?

Sankalp Srivastava Over a year ago

Sorry for the late response. Yes but this is the easiest way to do. You can use this method. There is nothing wrong with this method.

user3755020 Over a year ago

no problem , the way to explain is really appreciated, now can you please suggest me how can i learn about magic methods in php OOP.. thanks once again

|

Amin Jafari · Accepted Answer · 2014-06-27 07:16:17Z

0

you can try writing this piece of code where you want the script to be placed:

<?php
    if (!isset($_REQUEST['myVar'])) {
        echo '<script>
            alert("variable not exist");
            </script>';
    }
?>

answered Jun 27, 2014 at 7:16

Amin Jafari

7,2153 gold badges21 silver badges44 bronze badges

4 Comments

user1932079 Over a year ago

You've crossed your single quotes in the echo

VLAZ Over a year ago

And how is this different than what OP has?

Amin Jafari Over a year ago

@Vld it actually is not different, but it's another way to do it as an alternative!

user3755020 Over a year ago

is this code is valid :- <?php if(!isset($myPages)){ ?> var arrayVar = {step:"part5", activationId:activationId}; alert('not exist'); <?php } else {?>alert('hello how are you'); <?php } ?>

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