public String millisAsFormattedDate(long millis) {
        return PrimeSelenium.executeScript(
                    "return $.datepicker.formatDate(" + getWidgetByIdScript() + ".cfg.dateFormat, new Date(" + millis + "));");
    }
Gets the JS date value from the widget.

@return the JS date value or null
primefaces-selenium/primefaces-selenium-components/src/main/java/org/primefaces/selenium/component/Calendar.java