Introduction to HTML5: Part 1مقدمة في HTML5: الجزء الأول

A markup language that specifies the structure and content of documents that are displayed in web browsers.

Required in HTML5 documents so that browsers render the page in standards mode. Some browsers operate in quirks mode to maintain backward compatibility with pages that are not up-to-date with the latest standards.

Start with <!-- and end with -->. They improve readability; the browser ignores comments when rendering.

Start tag: the element name in angle brackets, e.g. <html>. End tag: the name preceded by a forward slash, e.g. </html>. Void elements do not have end tags.

Provides additional information about an element: a name and a value separated by an equals sign (=).

A nested element inside head. Appears in the title bar / browser tab and identifies bookmarks. Search engines use the title for indexing and when displaying results.

All text placed between <p> and </p> forms one paragraph.

Six heading elements, h1 through h6. h1 is the most significant heading and is rendered in the largest font; each successive heading is rendered in a progressively smaller font.

References or links to other resources, such as HTML5 documents and images. Browsers typically underline text hyperlinks and color them blue by default.

Anchors can link to an e-mail address using a mailto: URL. When a user clicks it, most browsers launch the default e-mail program to write a message to the linked address.

Specifies the image's location.

Every img element must have an alt attribute: text displayed if the client cannot render the image. Speech synthesizer software can speak it, so it should describe the image's contents.

Optional. If omitted, the browser uses the image's actual width and height. Images are measured in pixels.

Contain only attributes and do not mark up text. You can terminate them with a forward slash inside the closing angle bracket.

Written in the form &code; for special characters that cannot be rendered otherwise. The code can be a word abbreviation or a number (decimal or hexadecimal).

Inserts a horizontal rule.

Strikes through text.

Subscript text, e.g. x₁.

Superscript text, e.g. 10².

Specifies the script to which the form data will be sent (the form handler).

Nonvisual components that store any data you specify, such as e-mail addresses and file names.

The a tag can link to another section of the same document by specifying the element's id as the link's href, using the syntax #id.

content provides search engines with a list of words that describe a page, compared with words in search requests.

content provides a three- to four-line description of a site in sentence form, used by search engines to catalog the site; sometimes displayed in the search result.