code: @Override
    public boolean isScriptValid() {
      try {
        String script = getScriptContent();
        if (script.trim().length() == 0) {
          log.log(Level.FINE, "PAC script is empty. Skipping script!");
          return false;
        }
        if (script.indexOf("FindProxyForURL") == -1) {
          log.log(Level.FINE,
              "PAC script entry point FindProxyForURL not found. Skipping script!");
          return false;
        }
        return true;
      } catch (IOException e) {
        log.log(Level.FINE, "File reading error", e);
        return false;
      }
    }
docs: ***********************************************************************
  isScriptValid
  
  @see com.btr.proxy.selector.pac.PacScriptSource#isScriptValid()
  **********************************************************************