How to cache/refresh static resources (server and client side)

common.js

// Similar functionalities, same name as its PHP counterpart, located in Nest_url_helper.php
// @param  url  String: relative path of the source
function site_ver_url(url) {
  if(baseURL === undefined || baseURL == '') {
    return;
  }
  
  if(codeRevision === undefined) {
    codeRevision = 100;
  }
  
  // retrieve filename
  var filename = url.substring(url.lastIndexOf('/') + 1, url.lastIndexOf('.'));
  // retrieve file extension
  var fileExt = url.split('.').pop();
  // replace filename
  return (baseURL + url.replace(filename, filename + '.' + codeRevision));
}

config.php

/*
 |--------------------------------------------------------------------------
 | Code Revision
 |--------------------------------------------------------------------------
 | 
 | This version number will be altered when the branch source code is updated.
 | Make sure there is so special or space characters in between, else PHP and 
 | Javascript will have different values
 | E.g. "62+ p.67" in PHP will be "62+%20p.67" in JS
 |
 */
$config['code_revision'] = '62+p.67-100';

header.php

<script type="text/javascript">
  // this global variable will be used in common.js
  var codeRevision = '<?php echo $this->config->item('code_revision'); ?>';
</script>

<script type="text/javascript" src="<?= site_ver_url('assets/js/views/schedule.js'); ?>"></script>

MY_url_helper.php

<?php

/**
 * Auto-versioning.  Append last modified datetime to filename, .htaccess needs to have the corresponding rule
 * Similar function, same name in javascript, common.js
 * E.g. "assets/css/style.css" converts to "assets/css/style.1363054031.css"
 * @param  $url  String  Relative path
 * @return  String  Modified relative path
 */
if ( ! function_exists('site_ver_url')) {
  function site_ver_url($url) {
    $CI =& get_instance();
    
    // Get branch name, remove any '/' characters
    $parts = parse_url($CI->config->item('base_url'));
    $branch = strtok($parts['path'], '//');
    
    // Build new file path with version number attached
    $path = pathinfo($url);
    $ver = '.' . $CI->config->item('code_revision') . '.';
    
    return site_url($path['dirname'] . '/' . str_replace('.', $ver, $path['basename']));
  }
}

process.js

// Load the chosen service config javascript dynamically, 5 secs time limit (YUI2)
YAHOO.util.Get.script(site_ver_url('assets/js/' + module + '.js'), {
  onSuccess: formSuccess,
  onFailure: formFailure,
  onTimeout: formFailure,
  timeout: 5000,
});