/**
  * Runs the specified JavaScript snippet repeatedly 
  * until it evaluates to "true".
  *
  * @param  string  $script
  * @param  integer $timeout
  * @return string
  * @access public
  */
 public function waitForCondition($script, $timeout = NULL)
 {
     return $this->selenium->waitForCondition($script, $timeout);
 }