HTML is an abbreviation for HyperText Markup Language, a document format used to define web pages. HTML is characterized by content surrounded by elements (also called tags) which help describe the content. The HTML is typically rendered within a web browser for display to an end user.
Up until HTML5, HTML specifications were versioned. The Web Hypertext Application Technology Working Group (WHATWG) then moved to a new development model where the technology is a "living standard" and evolves continuously.
 Hello World
A minimalist Hello World example:
<html> <head> <title>Hello World!</title> </head> <body> <p>Hello World!</p> </body> </html>
Every HTML document must contain one top-level html element. Within that, there must be one head element and one body element. The head element must contain one title element. Any other elements within head and body are optional.
 HTML Elements
- Defines the enclosing content as being HTML. After document type markup, html is the root element which surrounds the entire contents of the page. (Required)
- Defines meta data typically not displayed directly within web pages, but useful to web browsers and crawlers. (Required)
- Indicates the base URL
- Always within head, defines the title of the page. It's used for display in web browser tabs and title bars. It's also used as a link title by most search engines. (Required)
- References other related documents, such as CSS, RSS, copyright, and search URLs.
- Text-based meta information, such as document description and keywords
- Defines external scripts or inline code to execute. This element is also available within the document body.
- Defines the main content of the web page. The content within the body tag defines what's displayed within the main window of the web browser.
- Defines an anchor, typically a link to another document, but can also be a name to represent a target within the current document.
- Denotes an abbreviation
- Contact information.
- Defines an image-map link to another document.
- Article content.
- Content which is separate from the main article. (Introduced in HTML 5)
- Specifies a direction override of the Unicode BiDi algorithm
- Defines a quotation block
- Line break
- Title of a cited work
- Description, to follow a dt term
- Deleted text
- Control for additional on-demand information (Introduced in HTML 5)
- Defining instance
- Generic block-level element
- Description list
- Line items within an ordered or unordered list (ol or ul)
- Highlighted text (Introduced in HTML 5)
- A scalar gauge (Introduced in HTML 5)
- Grouped navigational elements (Introduced in HTML 5)
- Designates an unordered list. The li elements within are typically rendered with numbers on their left.
- Defines a paragraph.
- Progress indicator
- Designates an unordered list. The li elements within are typically rendered with bullets, as opposed to an ordered list (ol) which are rendered with numbers.
- Defines external scripts or inline code to execute.
- Bold text
- Computer code for display (not execution)
- Italic text
- Emphasized text
- Strong text
- Generic text-level element - unlike div, does not directly affect formatting
- Table title (optional)
- Table column
- Column group (optional)
- The root element of a table description
- Table body, containing trs and tds (optional)
- Table column header, within a thead
- Table head, containing ths (optional)
- "Table data", a single cell within the table
- Table row
- Describes an audio stream. (Introduced in HTML 5)
- A graphical canvas which can be updated dynamically. (Introduced in HTML 5)
- Caption for a figure. (Introduced in HTML 5)
- A figure, typically associated with an article. (Introduced in HTML 5)
- A static image
- Media source (Introduced in HTML 5)
- Describes a video stream (Introduced in HTML 5)
- Defines a set of input elements used to submit data to a web server.
- Command with an associated action (Introduced in HTML 5)
- Options defined for other form controls (Introduced in HTML 5)
- Defines a data input field within a form.
- Calculation results (Introduced in HTML 5)