If you introduce the nesting rules of basic HTML web page labels, the first thing you need to talk about is the classification of elements. Elements can be divided into block-level elements and row-level elements. What are block-level elements? It can occupy a single line and set the width height, which is 100% by default. The line-level element is opposite to it. Its content determines its width height. As for special characters, it is regarded as text.
<!DOCTYPE html><html lang=en><head> <meta charset=UTF-8> <meta name=viewport content=width=device-width, initial-scale=1.0> <title> HTML block-level, line-level elements, special characters, nesting rules</title></head><body> <!-- Block element: Exclusive of one line, width and height, default width 100% --> Block element is divided into text class and container text class block elements: p, h1-h6 Container class block elements: div, table, tr, td, frame, ul>li, ol, dl, dt, dd (sequence) <!-- Line element: not exclusive of one line, width and height depend on content --> Line element: a img input strong em del span Special characters: text br   hr</body></html>The nesting rules are summarized as follows:
1. Block elements can be nested with line elements
2. Row elements can be nested
3. Line elements cannot be nested with block elements
4. Text block elements cannot be nested
5. Container block elements can be nested
The following basic concepts of html web pages, basic structure of html web pages, introduction of HTML basic tag picture text hyperlink list tables, interactive principles of html basic tag form implementation, single-check boxes, check boxes, drop-down boxes, and comparison of web page DIV+CSS layout and ifame traditional layout are all parts of HTML. Learning HTML mainly involves understanding its semantic nesting rules to build a page. As for the CSS and interactive logic of the page, JS will be the content to be practiced below!