The HTML <dialog> element represents a dialog box or other interactive component, such as an inspector or window. <form> elements can be integrated within a dialog by specifying them with the attribute method="dialog". When such a form is submitted, the dialog is closed with a returnValue attribute set to the value of the submit button used.
The HTML <div> element (or HTML Document Division Element) is the generic container for flow content, which does not inherently represent anything. It can be used to group elements for styling purposes (using the class or id attributes), or because they share attribute values, such as lang. It should be used only when no other semantic element (such as <article> or <nav>) is appropriate.
The HTML <hgroup> Element (HTML Headings Group Element) represents the heading of a section. It defines a single title that participates in the outline of the document as the heading of the implicit or explicit section that it belongs to.
The HTML <link> element specifies relationships between the current document and an external resource. Possible uses for this element include defining a relational framework for navigation. This Element is most used to link to style sheets.
The HTML Mark Element (<mark>) represents highlighted text, i.e., a run of text marked for reference purpose, due to its relevance in a particular context. For example it can be used in a page showing search results to highlight every instance of the searched-for word.
The HTML <menu> element represents a group of commands that a user can perform or activate. This includes both list menus, which might appear across the top of a screen, as well as context menus, such as those that might appear underneath a button after it has been clicked.
The HTML <nobr> element prevents a text from breaking into a new line automatically, so it is displayed on one long line and scrolling might be necessary. This tag is not standard HTML and should not be used. Instead use the CSS property white-space like this: