Add random version number to scripts and styles in WordPress

iworks_add_random_version.php

<?php
add_filter( 'script_loader_src', 'iworks_add_random_version', 10, 2 );                                          
add_filter( 'style_loader_src', 'iworks_add_random_version', 10, 2 );                                           
function iworks_add_random_version( $src, $handle ) {                                                           
    return add_query_arg( 'iv', rand(), $src );                                                                 
}