The alert under the echo function of a script does not work in php?

The below coding, includes two function in this program, one function inserts the dealers into database "insert_dealer" before which the a function checks if the particular dealer has already created an account, to do this, i have used function "check_email".

Now my problem is

echo "<script>
alert('Username already exist');
 </script>"

under the check_user function the alert works, after which the dealer is inserted into db, where

echo "<script>
 alert('Dealer's profile has been added. Login credentials are sent to their mail id.');
</script>

the alert does not work

THE NEW DEALER IS ADDED INTO DB, BUT THE ALERT ALONE IS NOT DISPLAYED..

please check the code below and suggest your ideas.

<?
include_once('config.php');

function insert_dealer($title, $fname, $lname, $email, $phone, $token)
{
mysql_query("SET NAMES utf8");
{   $user_query = "INSERT INTO dealer_tbl(title, firstname, lastname, email, phone, password, date_created, time_created)
          VALUES ('$title','$fname','$lname','$email','$phone',password('$token'), CURDATE(), CURTIME())";
}
$user_result = mysql_query($user_query);
// echo $user_query;
if (!$user_result)
{
    die('Error on query: ' . mysql_error());

}
else
{
    echo "<script>
    alert('Dealer's profile has been added. Login credentials are sent to their mail id.');
    window.location = './dealer_portal.php'</script>";
    /*header('Location: dealer_portal.php?status=1&uname='.$email.'&pwd='.$token);*/

}
}

function check_email($title, $fname, $lname, $email, $phone, $token)
{
mysql_query("SET NAMES utf8");
{   $dealer_query = "SELECT * FROM `dealer_tbl` WHERE `email` = '". $email ."'";
}
$result = mysql_query($dealer_query);
$num_rows = mysql_num_rows($result);
// echo $user_query;
if ($num_rows > 0)
{
    echo "<script>
    alert('Username already exist');
    window.location = './dealer_portal.php'</script>";

    return 0;
}else{
insert_dealer($title, $fname, $lname, $email, $phone, $token);
return 1;

}
}
?>

---

Quotes are placing problem, try something like this:

echo "<script>
    alert('Dealer\'s profile has been added. Login credentials are sent to their mail id.');
    </script>";

else you need to concatenate your strings & variables.