() && n.local_name() == atom)
            .and_then(|n| n.downcast().map(Root::from_ref))
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-thead
    // https://html.spec.whatwg.org/multipage/#dom-table-tfoot
    fn set_first_section_of_type(&self,
                                    atom: &Atom,
                                    section: Option<&HTMLTableSectionElement>,
                                    reference_predicate: P)
                                    -> ErrorResult
                                    where P: FnMut(&Root) -> bool {
        if let Some(e) = section {
            if e.upcast::().local_name() != atom {
                return Err(Error::HierarchyRequest)
            }
        }
        self.delete_first_section_of_type(atom);
        let node = self.upcast::();
        if let Some(section) = section {
            let reference_element = node.child_elements().find(reference_predicate);
            let reference_node = reference_element.r().map(|e| e.upcast());
            try!(node.InsertBefore(section.upcast(), reference_node));
        }
        Ok(())
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-createthead
    // https://html.spec.whatwg.org/multipage/#dom-table-createtfoot
    fn create_section_of_type(&self, atom: &Atom) -> Root {
        if let Some(section) = self.get_first_section_of_type(atom) {
            return section
        }
        let section = HTMLTableSectionElement::new(atom.clone(),
                                                   None,
                                                   document_from_node(self).r());
        match atom {
            &atom!("thead") => self.SetTHead(Some(§ion)),
            &atom!("tfoot") => self.SetTFoot(Some(§ion)),
            _ => unreachable!("unexpected section type")
        }.expect("unexpected section type");
        section
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-deletethead
    // https://html.spec.whatwg.org/multipage/#dom-table-deletetfoot
    fn delete_first_section_of_type(&self, atom: &Atom) {
        if let Some(thead) = self.get_first_section_of_type(atom) {
            thead.upcast::().remove_self();
        }
    }
}
impl HTMLTableElementMethods for HTMLTableElement {
    // https://html.spec.whatwg.org/multipage/#dom-table-rows
    fn Rows(&self) -> Root {
        #[allow(unrooted_must_root)]
        #[derive(JSTraceable, HeapSizeOf)]
        struct TableRowFilter {
            sections: Vec>
        }
        impl CollectionFilter for TableRowFilter {
            fn filter(&self, elem: &Element, root: &Node) -> bool {
                elem.is::()
                    && (root.is_parent_of(elem.upcast())
                        || self.sections.iter().any(|ref section| section.is_parent_of(elem.upcast())))
            }
        }
        let filter = TableRowFilter {
            sections: self.upcast::()
                          .children()
                          .filter_map(|ref node|
                                node.downcast::().map(|_| JS::from_rooted(node)))
                          .collect()
        };
        HTMLCollection::new(window_from_node(self).r(), self.upcast(), box filter)
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-caption
    fn GetCaption(&self) -> Option> {
        self.upcast::().children().filter_map(Root::downcast).next()
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-caption
    fn SetCaption(&self, new_caption: Option<&HTMLTableCaptionElement>) {
        if let Some(ref caption) = self.GetCaption() {
            caption.upcast::().remove_self();
        }
        if let Some(caption) = new_caption {
            let node = self.upcast::();
            node.InsertBefore(caption.upcast(), node.GetFirstChild().r())
                .expect("Insertion failed");
        }
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-createcaption
    fn CreateCaption(&self) -> Root {
        let caption = match self.GetCaption() {
            Some(caption) => caption,
            None => {
                let caption = HTMLTableCaptionElement::new(atom!("caption"),
                                                           None,
                                                           document_from_node(self).r());
                self.SetCaption(Some(caption.r()));
                caption
            }
        };
        Root::upcast(caption)
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-deletecaption
    fn DeleteCaption(&self) {
        if let Some(caption) = self.GetCaption() {
            caption.upcast::().remove_self();
        }
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-thead
    fn GetTHead(&self) -> Option> {
        self.get_first_section_of_type(&atom!("thead"))
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-thead
    fn SetTHead(&self, thead: Option<&HTMLTableSectionElement>) -> ErrorResult {
        self.set_first_section_of_type(&atom!("thead"), thead, |n| {
            !n.is::() && !n.is::()
        })
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-createthead
    fn CreateTHead(&self) -> Root {
        self.create_section_of_type(&atom!("thead"))
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-deletethead
    fn DeleteTHead(&self) {
        self.delete_first_section_of_type(&atom!("thead"))
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-tfoot
    fn GetTFoot(&self) -> Option> {
        self.get_first_section_of_type(&atom!("tfoot"))
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-tfoot
    fn SetTFoot(&self, tfoot: Option<&HTMLTableSectionElement>) -> ErrorResult {
        self.set_first_section_of_type(&atom!("tfoot"), tfoot, |n| {
            if n.is::() || n.is::() {
                return false;
            }
            if n.is::() {
                let name = n.local_name();
                if name == &atom!("thead") || name == &atom!("tbody") {
                    return false;
                }
            }
            true
        })
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-createtfoot
    fn CreateTFoot(&self) -> Root {
        self.create_section_of_type(&atom!("tfoot"))
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-deletetfoot
    fn DeleteTFoot(&self) {
        self.delete_first_section_of_type(&atom!("tfoot"))
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-tbodies
    fn TBodies(&self) -> Root {
        #[derive(JSTraceable)]
        struct TBodiesFilter;
        impl CollectionFilter for TBodiesFilter {
            fn filter(&self, elem: &Element, root: &Node) -> bool {
                elem.is::()
                    && elem.local_name() == &atom!("tbody")
                    && elem.upcast::().GetParentNode().r() == Some(root)
            }
        }
        self.tbodies.or_init(|| {
            let window = window_from_node(self);
            let filter = box TBodiesFilter;
            HTMLCollection::create(window.r(), self.upcast(), filter)
        })
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-createtbody
    fn CreateTBody(&self) -> Root {
        let tbody = HTMLTableSectionElement::new(atom!("tbody"),
                                                 None,
                                                 document_from_node(self).r());
        let node = self.upcast::();
        let last_tbody =
            node.rev_children()
                .filter_map(Root::downcast::)
                .find(|n| n.is::() && n.local_name() == &atom!("tbody"));
        let reference_element =
            last_tbody.and_then(|t| t.upcast::().GetNextSibling());
        node.InsertBefore(tbody.upcast(), reference_element.r())
            .expect("Insertion failed");
        tbody
    }
    // https://html.spec.whatwg.org/multipage/#dom-table-bgcolor
    make_getter!(BgColor, "bgcolor");
    // https://html.spec.whatwg.org/multipage/#dom-table-bgcolor
    make_legacy_color_setter!(SetBgColor, "bgcolor");
    // https://html.spec.whatwg.org/multipage/#dom-table-width
    make_getter!(Width, "width");
    // https://html.spec.whatwg.org/multipage/#dom-table-width
    make_nonzero_dimension_setter!(SetWidth, "width");
}
pub trait HTMLTableElementLayoutHelpers {
    fn get_background_color(&self) -> Option;
    fn get_border(&self) -> Option;
    fn get_cellspacing(&self) -> Option;
    fn get_width(&self) -> LengthOrPercentageOrAuto;
}
impl HTMLTableElementLayoutHelpers for LayoutJS {
    #[allow(unsafe_code)]
    fn get_background_color(&self) -> Option {
        unsafe {
            (*self.upcast::().unsafe_get())
                .get_attr_for_layout(&ns!(), &atom!("bgcolor"))
                .and_then(AttrValue::as_color)
                .cloned()
        }
    }
    #[allow(unsafe_code)]
    fn get_border(&self) -> Option {
        unsafe {
            (*self.unsafe_get()).border.get()
        }
    }
    #[allow(unsafe_code)]
    fn get_cellspacing(&self) -> Option {
        unsafe {
            (*self.unsafe_get()).cellspacing.get()
        }
    }
    #[allow(unsafe_code)]
    fn get_width(&self) -> LengthOrPercentageOrAuto {
        unsafe {
            (*self.upcast::().unsafe_get())
                .get_attr_for_layout(&ns!(), &atom!("width"))
                .map(AttrValue::as_dimension)
                .cloned()
                .unwrap_or(LengthOrPercentageOrAuto::Auto)
        }
    }
}
impl VirtualMethods for HTMLTableElement {
    fn super_type(&self) -> Option<&VirtualMethods> {
        Some(self.upcast::() as &VirtualMethods)
    }
    fn attribute_mutated(&self, attr: &Attr, mutation: AttributeMutation) {
        self.super_type().unwrap().attribute_mutated(attr, mutation);
        match *attr.local_name() {
            atom!("border") => {
                // According to HTML5 ยง 14.3.9, invalid values map to 1px.
                self.border.set(mutation.new_value(attr).map(|value| {
                    parse_unsigned_integer(value.chars()).unwrap_or(1)
                }));
            }
            atom!("cellspacing") => {
                self.cellspacing.set(mutation.new_value(attr).and_then(|value| {
                    parse_unsigned_integer(value.chars())
                }));
            },
            _ => {},
        }
    }
    fn parse_plain_attribute(&self, local_name: &Atom, value: DOMString) -> AttrValue {
        match *local_name {
            atom!("border") => AttrValue::from_u32(value, 1),
            atom!("width") => AttrValue::from_nonzero_dimension(value),
            atom!("bgcolor") => AttrValue::from_legacy_color(value),
            _ => self.super_type().unwrap().parse_plain_attribute(local_name, value),
        }
    }
}