code: public static Object getAttribute(UIComponent component, String attributeName) {
  		Object value = component.getPassThroughAttributes().get(attributeName);
  		if (null == value) {
  			value = component.getAttributes().get(attributeName);
  		}
  		if (null == value) {
  			if (!attributeName.equals(attributeName.toLowerCase())) {
  				return getAttribute(component, attributeName.toLowerCase());
  			}
  		}
  		if (value instanceof ValueExpression) {
  			value = ((ValueExpression) value).getValue(FacesContext.getCurrentInstance().getELContext());
  		}
  		return value;
  	}
docs: Apache MyFaces make HMTL attributes of HTML elements
  pass-through-attributes. This method finds the attribute, no matter
  whether it is stored as an ordinary or as an pass-through-attribute.