else System.err.println("unhandled value-type in RuleNormalizer.expandBackgroundPosition");
    private void expandBackgroundPosition(CSSStyleRule rule) {        CSSStyleDeclaration dec = rule.getStyle();        CSSValue val = dec.getPropertyCSSValue("background-position");        String prio = dec.getPropertyPriority("background-position");        if(val.getCssValueType() == val.CSS_VALUE_LIST) {            //u.p("val = " + val);            return;        }        if(val.getCssValueType() == val.CSS_PRIMITIVE_VALUE) {            //u.p("val = " + val);            String str = val.getCssText();            if(str.startsWith("top")) { dec.setProperty("background-position","50% 0%",prio); }            if(str.startsWith("bottom")) { dec.setProperty("background-position","50% 100%",prio); }            if(str.startsWith("left")) { dec.setProperty("background-position","0% 50%",prio); }            if(str.startsWith("right")) { dec.setProperty("background-position","100% 50%",prio); }            return;        }    }