- htmlspecialchars: documentation ( source)
- json_encode: documentation ( source)
<?php
$val = array("foo" => "to the so called 'bar'");
$data = htmlspecialchars(json_encode($val), ENT_QUOTES);
echo <<<HTML
<script type='text/javascript'>
var data = '$data';
var json = JSON.parse(data);
</script>
HTML;
?>