How can developers convert JS timestamps to UNIX timestamps in PHP for accurate date and time representation?

When converting JS timestamps to UNIX timestamps in PHP for accurate date and time representation, developers need to account for the difference in how timestamps are represented in each language. JavaScript timestamps are typically in milliseconds since the Unix epoch, while PHP timestamps are usually in seconds since the Unix epoch. To convert a JS timestamp to a UNIX timestamp in PHP, developers need to divide the JS timestamp by 1000 to convert it from milliseconds to seconds.

$js_timestamp = 1615588800000; // Example JS timestamp in milliseconds
$unix_timestamp = $js_timestamp / 1000; // Convert JS timestamp to UNIX timestamp in seconds

echo date('Y-m-d H:i:s', $unix_timestamp); // Output the converted UNIX timestamp in a readable date format