Drupal 7 hook method to remove cache busting query strings on css and js files. Related to this post https://drupal.org/node/242875

template.php

<?php

/**
 * Implements hook_process_html
 */
function templatenamespace_process_html(&$vars) {

  $search = array('scripts' => 'src=', 'styles' => 'href=', 'styles' => '@import\surl\(');
  foreach ( $search as $var => $word ) {
    if ( !empty($vars[$var]) ) {
      $lines = explode("\n", $vars[$var]);
      $result = array();
      foreach($lines as $line) {
        $matches = array();
        if ( preg_match('/' . $word . '"(.*)"/', $line, $matches) ) {
          global $language;
          $match = $matches[1];
          $replacement = $matches[1];
          // remove the ? and everything behind it
          $pos = strpos($replacement, '?');
          $replaced = $line;
          if ( $pos !== FALSE ) {
            $replacement = substr($replacement, 0, $pos);
            $replaced = str_ireplace($match, $replacement, $line);
          }
          $result[] = $replaced;
        }
        else {
          $result[] = $line;
        }
      }   
      if ( !empty($result) ) {
        $vars[$var] = implode("\n", $result);
      }
    }
  }

}

?>