Block inline pseudo emelemts

The document describes various block level elements, inline elements, pseudo elements, pseudo classes and JavaScript events in HTML and CSS. Some key block level elements include <div>, <header>, <footer>, <section>, and <article>. Important inline elements are <a>, <b>, <em>, <img>, and <input>. Common pseudo elements are ::first-line, ::before and ::after. Frequently used pseudo classes include :hover, :link, :visited, :active and :focus. Common JavaScript events are onclick, onmouseover, onload and onsubmit.