How can I force clients to refresh JavaScript files?

Question

We are currently working in a private beta and so are still in the process of making fairly rapid changes, although obviously as usage is starting to ramp up, we will be slo

Answer 1

In PHP:

function latest_version($file_name){
    echo $file_name."?".filemtime($_SERVER['DOCUMENT_ROOT'] .$file_name);
}

In HTML: