HTML ( Hypertext Markup Language ) elements historically were categorized as either "block-level" elements or "inline-level" elements. Since this is a presentational characteristic it is nowadays specified by CSS in the 流式布局 . A Block-level element occupies the entire horizontal space of its parent element (container), and vertical space equal to the height of its contents, thereby creating a "block". In this article, we'll examine HTML block-level elements and how they differ from inline-level elements .
Browsers typically display the block-level element with a newline both before and after the element. You can visualize them as a stack of boxes.
A block-level element always starts on a new line and takes up the full width available (stretches out to the left and right as far as it can).
The following example demonstrates the block-level element's influence:
<p>This paragraph is a block-level element; its background has been colored to display the paragraph's parent element.</p>
p { background-color: #8ABB55; }
<body>
元素。
There are a couple of key differences between block-level elements and inline elements:
Generally, block-level elements may contain inline elements and (sometimes) other block-level elements. Inherent in this structural distinction is the idea that block elements create "larger" structures than inline elements.
By default, block-level elements begin on new lines, but inline elements can start anywhere in a line.
The distinction of block-level vs. inline elements was used in HTML specifications up to 4.01. In HTML5, this binary distinction is replaced with a more complex set of content categories . While the "inline" category roughly corresponds to the category of 措词内容 , the "block-level" category doesn't directly correspond to any HTML5 content category, but "block-level" and "inline" elements combined together correspond to the flow content in HTML5. There are also additional categories, e.g. interactive content .
The following is a complete list of all HTML "block-level" elements (although "block-level" is not technically defined for elements that are new in HTML5).
<address>
Contact information.
<article>
Article content.
<aside>
Aside content.
<blockquote>
Long ("block") quotation.
<details>
Disclosure widget.
<dialog>
Dialog box.
<dd>
Describes a term in a description list.
<div>
Document division.
<dl>
Description list.
<dt>
Description list term.
<fieldset>
Field set label.
<figcaption>
Figure caption.
<figure>
<figcaption>
).
<footer>
Section or page footer.
<form>
Input form.
<h1>
,
<h2>
,
<h3>
,
<h4>
,
<h5>
,
<h6>
Heading levels 1-6.
<header>
Section or page header.
<hgroup>
Groups header information.
<hr>
Horizontal rule (dividing line).
<li>
List item.
<main>
Contains the central content unique to this document.
<nav>
Contains navigation links.
<ol>
Ordered list.
<p>
Paragraph.
<pre>
Preformatted text.
<section>
Section of a web page.
<table>
Table.
<ul>
Unordered list.