HTML - The Structural Layer

We'll do most of this in class

HTML describes the structure of pages

What is a markup language?

  • It's a collection of codes, embedded in a document, that explain the meaning or desired formatting of the marked text
  • It's a way of describing, using instructions buried in the document, what the document is supposed to look like
  • Every electronic text processing tool uses some kind of markup language, though you may not necessarily be able to see the commands


HTML follows the same three-part-instruction model that command line instructions used in UNIX or LINUX.

UNIX/LINUX ⇒ command argument value
HTML ⇒ tag attribute value

So an HTML tag is a form of a command, but this tag (command) is directed at the browser.

HTML Elements and tags

An element is composed of content that is to be displayed and tags that tell the browser what structure the content is to be understood to be.

For instance, these tags tell the content of the element how to display.

<b>content</b> tells the browser to show the word "content" as bold, or content

For another instance, these tags tell the content of the element how to display.

<i>content</i> tells the browser to show the word "content" as italicized, or content

Attributes and values of tags

Some elements - such as a Heading 4
can take
attributes that define the properties of the element - such as a style
values - such as centering

<h4 style="text-align:center;">centering a Heading 4</h4>
tells the browser to show the words "centering a Heading 4" in Heading 4 style and centered, or

centering a Heading 4


They follow rules about nesting and placement.

In general, both sides of the content must be balanced and consistent.

<p><h3 style="text-align:right;">the marked-up content</h3></p>
tells the browser to
open paragraph
    open heading 3 in a style in which the text is displayed to the right of the line
        the marked-up content
    close heading 3
close paragraph

in mirrored order
or, as it will display

the marked-up content


HyperText Document structure

  1. The <!DOCTYPE> declaration must be the very first thing in your HTML document, before the <html> tag. The <!DOCTYPE> declaration is not an HTML tag; it is an instruction to the web browser about what version of HTML the page is written in.
  2. <html> the outermost element, indicates that the enclosed text is html and therefore must use an html-capable program to open it
  3. <head> the first element inside <html> is the HEAD
    • a container for information about the document; this is where one might place meta-information about the document as well as the <title>page title</title>
    • remember, balanced and consistent; one must close the HEAD, </head>
  4. <body> the BODY element contains all the text and other material that is to be displayed
    • and, of course, the document is balanced as it is closed, </body>
  5. and consistent, as HTML is closed as well - </html>

So the structure should look like

<!DOCTYPE html version>
<!-- this is a comment; the html version should be specified -->
        <title>page title</title>

        <p>a paragraph in the body of the page</p>
        <!-- this is a comment -->

Although we can get away without putting end tags on elements (because many browsers are lax about it), we will adopt the habit of always closing any tag we open so that we are compliant with current and future standards.


        <title> INLS201-001 Fall 2017 Information Tools | Sample Page </title>
        <meta name ="description" content ="sample page for INLS201-001 Fall 2017 Information Tools"  />
        <meta name ="keywords" content ="information literacy, information tools, information, tasks, hard coding"  />
        <meta http-equiv ="content-type" content ="text/html; charset=UTF-8"  />
        <link rel ="stylesheet" type ="text/css" href ="notyet.sample-style.css"  />

Metadata typically define document title, styles, links, scripts, and other meta information.