Javascript cant get value from PHP variable?

Question

I want make data exist checker. data.check.php:

<?php
    $nick   = mysql_real_escape_string($_POST['nick']);
    $query = mysql_query("select * from tb_user WHERE nick='$nick'");
    $nick_exist = mysql_num_rows($query);
?>

<script language="javascript" type="text/javascript">
    var nick_exist = "<?php echo $nick_exist; ?>";
</script>

and this for $POST data input.data.js

var v_nick = $('input:text[name=nick]').val();
$.post('data.check.php', {nick: v_nick} ,function() {
    if(nick_exist){
        window.alert('Choose another nick please!');
    }
});

I dont know where is the problem and my windows.alert is not running :(

thanks u

just show us what is you html gererated is <script language="javascript" type="text/javascript"> var nick_exist = ""; </script> ??? — Alex
– Alex, Commented Feb 1, 2015 at 13:10
make the php file to print 'true' or 'false', and use the printed to make the $.post inside condition $.post('data.check.php', {nick: v_nick} ,function(response) { alert(response); } — Yair.R
– Yair.R, Commented Feb 1, 2015 at 13:11
I agree with @Yair.R you even don't need that <script language="javascript" type="text/javascript"> var nick_exist = "<?php echo $nick_exist; ?>"; </script> just echo $nick_exist; to the stream. and check response on javascript side — Alex
– Alex, Commented Feb 1, 2015 at 13:14
use can print a json in data.check.php page and get json by jquery .ajax — Javad Khodadadi
– Javad Khodadadi, Commented Feb 1, 2015 at 13:18

Suchit kumar · Accepted Answer · 2015-02-01 15:34:48Z

1

try like this get the count in php then return it to js:

NOTE: Please do not use mysql it is deprecated now start using mysqli or pdo.

data.check.php:

<?php
    $nick   = mysql_real_escape_string($_POST['nick']);
    $query = mysql_query("select * from tb_user WHERE nick='$nick'");
    $nick_exist = mysql_num_rows($query);
    echo json_encode(array('count'=> $nick_exist));//send result to javascript
?>

input.data.js

var v_nick = $('input:text[name=nick]').val();
$.post('data.check.php', {nick: v_nick} ,function(resp) {
var resp=JSON.parse(resp);
    if(resp.count){
        window.alert('Choose another nick please!');
    }
});

edited Feb 1, 2015 at 15:34

answered Feb 1, 2015 at 13:18

Suchit kumar

11.9k3 gold badges26 silver badges46 bronze badges

Sign up to request clarification or add additional context in comments.

8 Comments

Yair.R Over a year ago

$nick_exist will return a number in the php, so the JS condition you have posted is wrong :)

Yair.R Over a year ago

if(parseInt(resp.count) > 0)

Suchit kumar Over a year ago

it is integer value already so no need to check on front-end.

Yair.R Over a year ago

But you must check if its bigger than 0, or it will always return true

Suchit kumar Over a year ago

0 means false any non 0 is true value.

|

Collectives™ on Stack Overflow

Javascript cant get value from PHP variable?

1 Answer 1

8 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

8 Comments

Your Answer

Sign up or log in

Post as a guest

Related