The HTML <shadow> element is used as a shadow DOM insertion point. You might use it if you have created multiple shadow roots under a shadow host. It is not useful in ordinary HTML. It is used with Web Components.
HTML (Hypertext Markup Language) elements are usually "inline" elements or "block-level" elements. An inline element occupies only the space bounded by the tags that define the inline element. The following example demonstrates the inline element's influence:
The CSS ::after pseudo-element matches a virtual last child of the selected element. It is typically used to add cosmetic content to an element by using the content CSS property. This element is inline by default.
The ::-ms-fill CSS pseudo-element represents the filled-in portion of a <progress> element. This pseudo-element is non-standard and specific to Internet Explorer 10+, hence the vendor prefix.
The ::selection CSS pseudo-element applies rules to the portion of a document that has been highlighted (e.g. selected with the mouse or another pointing device) by the user.
The ::-webkit-progress-bar CSS pseudo-element represents the entire bar of a <progress> element. Normally it's only visible as the unfilled portion of the bar, since by default it's rendered below the ::-webkit-progress-value pseudo-element. It is a child of the ::-webkit-progress-inner-element pseudo-element and the parent of the ::-webkit-progress-value pseudo-element.
The ::-webkit-progress-inner-element CSS pseudo-element represents the outermost, container pseudo-element of the <progress> element. It is the parent of the ::-webkit-progress-bar pseudo-element.
The ::-webkit-progress-value CSS pseudo-element represents the filled-in portion of the bar of a <progress> element. It is a child of the ::-webkit-progress-bar pseudo-element.
Fired when the code in a <script> element declared in an HTML document is about to start executing. Does not fire if the element is added dynamically, eg with appendChild().
The Element.attributes property returns a live collection of all attribute nodes registered to the specified node. It is a NamedNodeMap, not an Array, so it has no Array methods and the Attr nodes' indexes may differ among browsers. To be more specific, attributes is a key/value pair of strings that represents any information regarding that attribute.
The Element.classList is a read-only property which returns a live DOMTokenList collection of the class attributes of the element.
Returns the specified attribute of the specified element, as an Attr node.
The Element.getElementsByClassName() method returns a live HTMLCollection containing all child elements which have all of the given class names. When called on the document object, the complete document is searched, including the root node.
The Element.getElementsByTagName() method returns a live HTMLCollection of elements with the given tag name. The subtree underneath the specified element is searched, excluding the element itself. The returned list is live, meaning that it updates itself with the DOM tree automatically. Consequently, there is no need to call several times Element.getElementsByTagName() with the same element and arguments.
hasAttributeNS returns a boolean value indicating whether the current element has the specified attribute.
The Element.hasAttributes() method returns a Boolean value, true or false, indicating if the current element has any attributes or not.
The Element.id property represents the element's identifier, reflecting the id global attribute.
The insertAdjacentElement() method inserts a given element node at a given position relative to the element it is invoked upon.