$re = '/"bookIds"\s*:\s*\[([^\]]+?)]/m';
$str = '<html>
<head>
</head>
<body>
<script type="text/javascript">
... more code ...
},
"bookIds" : [
"abc123",
"qwe456",
"asd789"
],
... more code, and in another json:
},
"bookIds" : [
"foo111",
"bar222",
"baz333"
],
... more code ...
</script>
</body>
</html>';
preg_match($re, $str, $matches, PREG_OFFSET_CAPTURE, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php