将PHP字符串数组作为JSON传递给JavaScript数组不起作用？

Question

I'm trying to transform an array from PHP to JavaScript but it doesn't seem to work. Here's my PHP code query.php :

$query = 'SELECT coupon FROM '.$disc;
$coupdb = array();
$results = $newdb->get_results($query);
foreach( $results as $result )
$coupdb[] = $result->coupon;

echo $coupdb[0]; //This shows perfectly the content but I want to send this array to a Javascript file.

I've tried too with JSON:

$coupdb_js = json_encode($coupdb);

Here's my JavaScript file discount.js :

var coupdb = <?php echo $coupdb ?>;
alert(coupdb[0]);

And with JSON:

var coupdb = <?php echo $coupdb_js ?>;
alert(coupdb[0]);

Answer 1

@Jon shows me an "Unexpected token < "... It takes the <? as unknown token.

So your PHP isn't being processed. If this is in a .js file, it won't work unless the server is set up to process those files (bad idea)

Instead, this should probably be in a <script> tag in your HTML, or perhaps better as an AJAX call.

Answer 2

Finally I've found a way, It's an easy way but maybe not the best one :)

From my php I've sent the coupdb variable catched from bbdd to javascript file:

<?php
$DB_USER="dbuser";
$DB_PASSWORD="passdb";
$DB_NAME="dbname";
$DB_HOST="dbhost";

$newdb = new wpdb($DB_USER, $DB_PASSWORD, $DB_NAME, $DB_HOST);
$disc="discounts";


$query = 'SELECT coupon FROM '.$disc;
        $coupdb = array();
        $results = $newdb->get_results($query);
        foreach( $results as $result )
        $coupdb[] = $result->coupon;

?>
<script type="text/javascript">
    var coupdb = <?php echo json_encode($coupdb); ?>;
</script>

And in js file I used the variable normally:

alert (coupdb[0]);