jsDump() - Log a PHP variable to javascript console.

example.php

<?php
// Somewhere in your code…
jsDump($var1, 'var1', __FILE__, __LINE__); // TODO: remove me for production.
jsDump($var2, 'var2', __FILE__, __LINE__); // TODO: remove me for production.
?>

Utilities.inc.php

<?php
/*
* Log a PHP variable to javascript console. Relies on getDump(), below.
*
* @access   public
* @param    mixed   $var      The variable to dump.
* @param    string  $prefix   A short note to print before the output to make identifying output easier.
* @param    string  $file     The value of __FILE__.
* @param    string  $line     The value of __LINE__.
* @return   null
* @author   Quinn Comendant <quinn@strangecode.com>
*/
function jsDump($var, $prefix='jsDump', $file='-', $line='-')
{
    if (!empty($var)) {
        ?>
        <script type="text/javascript" charset="utf-8">
        /* <![CDATA[ */
        window.console && console.log('<?php printf('%s: %s (on line %s of %s)', $prefix, str_replace("'", "\\'", getDump($var, true)), $line, $file); ?>');
        /* ]]> */
        </script>
        <?php
    }
}

/*
* Return a string version of any variable, optionally serialized on one line.
*
* @access   public
* @param    mixed   $var        The variable to dump.
* @param    bool    $serialize  If true, remove line-endings. Useful for logging variables.
* @return   string              The dumped variable.
* @author   Quinn Comendant <quinn@strangecode.com>
*/
function getDump($var, $serialize=false)
{
    ob_start();
    print_r($var);
    $d = ob_get_contents();
    ob_end_clean();
    return $serialize ? preg_replace('/\s+/m', ' ', $d) : $d;
}