Passing a variable from PHP to jQuery on page load

Question

I'm trying to take a reference variable from the url, and query my database when the user first visits the page. I then need to take this results and plot on google maps.

<?php 
    include('storelocator/db/config.php');
    include('storelocator/db/db.php');  

    if(isset($_GET['ref'])){

        $ref = stripslashes($_GET['ref']);

        $sql = "SELECT * FROM `markers` WHERE `ref` = \"".$_GET['ref']."\"";

        $result = mysql_query($sql);    
        $row = mysql_fetch_row($result);
        print_r($row);
    }
?>

This is my code at the top of my index page, it works fine, the print_r gives the correct results. I'm just not sure how to pass these results to jQuery to be plotted. (I know how to plot, I basically need to know how to pass a variable $row['latlng'] to jQuery.)

thanks

thanks for the quick replies. echoing out the variable works, I'm wondering if this considered bad practise, because now my page begins with a <script> element. — michael
– michael, Commented May 31, 2011 at 13:19
The obvious answer is to do the "echoing" in the appropriate place in your document — Phil
– Phil, Commented May 31, 2011 at 13:21

Phil · Accepted Answer · 2011-05-31 13:18:10Z

2

Something like this

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

Now the markers JavaScript variable will be available to any scripts following the above.

You can access associative entries from the PHP $row array using

var latlng = markers.latlng;

While we're here, you should protect your query from SQL injection. Whilst I always recommend using PDO and parameter binding, a quick fix for you would be

$ref = get_magic_quotes_gpc() ? stripslashes($_GET['ref']) : $_GET['ref'];
$sql = sprintf("SELECT * FROM `markers` WHERE `ref` = '%s'",
               mysql_real_escape_string($ref));

edited May 31, 2011 at 13:18

answered May 31, 2011 at 13:13

Phil

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1 Comment

Salman Arshad Over a year ago

+1 for using json_encode which takes care of escaping special characters.

hsz · Accepted Answer · 2011-05-31 13:11:57Z

1

In line with

print_r($row);

put:

echo '<script type="text/javascript">';
echo 'var latlng = "' . $row['latlng'] . '";';
echo '</script>';

This is the way to pass data to JavaScript. ;)

answered May 31, 2011 at 13:11

hsz

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Comments

James.Xu · Accepted Answer · 2011-05-31 13:13:03Z

0

the following code pass your data to the javascript variable: 'data'

echo "<script>var data='".$row['latlng']."';</script>"

answered May 31, 2011 at 13:13

James.Xu

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