Lab 1: HTML Basics

🎯 Lab Objective

In this lab, you will learn the fundamental concepts of HTML documents.

This lab teaches the following concepts:

1. HTML Elements
2. HTML Tags
3. Nesting Elements
4. Element Attributes
5. Hyperlinks

Table of Contents

The labs are held in Owheo, G.37 or G.38 (Lab E or Lab F). The lab exercises are designed to be viewed on Google Chrome. You may instead use your own computer, but you will have to install some development tools.

If you haven’t logged into lab computers before, your login is the same as your your university login. If you cannot log in, ask a demonstrator for help (or anyone else nearby).

Visual Studio Code (VSC) is a flexible IDE designed for modern software development. Conveniently it is already installed on the lab computers.

✅ Tip

If using the lab computers, use the shortcut to VS Code under Coursework K:\

This shortcut tells VS Code to use J:\ Drive for settings/extensions. This way your settings will load on any lab computer.

• C:\ local storage
• H:\ home drive (slow)
• J:\ Warpdrive (fast)
• K:\ Coursework (read-only — we use this for sharing files with you)

To assist our web development we will install the “Live Server” extension, which will allow us to preview our HTML documents as we write them.

📝 Task 1: Get Visual Studio Code running

1. If working from your own computer
   • download and install Visual Studio Code
2. Open Visual Studio Code
3. Install the “Live Server” Extension
   1. Open Extension Marketplace
   2. Search “Live Server”
   3. Click Install

✅ Keyboard Shortcuts

Knowing all the features (and keyboard shortcuts) is crucial to being a productive developer.

Visual Studio Code keyboard shortcuts:

• Windows
  • https://code.visualstudio.com/shortcuts/keyboard-shortcuts-windows.pdf
• macOS
  • https://code.visualstudio.com/shortcuts/keyboard-shortcuts-macos.pdf

HTML is not a programming language, it is a declarative language. Programming languages like Python or Java tell the computer how to do things. Declarative languages like HTML tell the computer what it should do. That’s not a great explanation, but it will become clear soon.

Programming languages have control flow. The code defines an order of instructions to be executed. The order of these instructions can be changed with conditionals (like if) and loops (like while). In HTML there is no control flow.

We still write HTML in plain text saved to files; with the .html extension. Web browsers read .html files and render the document. Let’s take a look a simple example. Below is “hello world” in HTML.

We will explain what everything means shortly.

📝 Task 2: Hello World in HTML

1. Create a new folder for this lab
   • name it something useful, like “lab01”
2. From Visual Studio Code open this folder
   • File > Open Folder
3. Create a new file in this folder
   • Ctrl+n or ⌘+n
   • save the file as hello_world.html
4. Type the hello world example above (and save)
5. Start the Live Server

There are a few ways to start Live Server:

• A: Right Click “hello_world.html” > Open with Live Server
• B: Click “Go Live” in bottom right

• C: search for “live server” in the Command Palette. Open the Command Palette with the keyboard shortcut ⌘+P (macOS) or Ctrl+Shift+P (Win/Linux).

If Live Server doesn’t open a web browser, just visit: 127.0.0.1:5500/hello_world.html in your preferred browser. Most modern browsers should render the smiley emoji properly, but older browsers may render it incorrectly (as shown in the following screenshot). We will fix this shortly.

✅ Web Servers

Web servers are programs that “serve” HTML files (and other files). You don’t always need a web server to view an HTML document, but it will make things easier as our projects grow.

Thankfully, the Live Server extension handles everything for us.

There are many ways to find bugs in HTML documents. The W3C Validator is probably the best tool to find errors in .html files, like our hello world example.

📝 Task 3: Validate helloworld.html

1. Upload your .html file to the W3C Validator
   • Link here: https://validator.w3.org/#validate_by_upload.
2. Read through all the errors and warnings before continuing.

✅ W3C

The W3C (World Wide Web Consortium) is a community dedicated to developing international standards for the World Wide Web. The consortium was founded, and is currently led by the inventor of the World Wide Web, Tim Berners-Lee. Essentially, the W3C recommendations are the gold standard.

The validator should report 3 errors and 1 warning, and yet, a modern browser can render the document mostly okay. Modern browsers are very tolerant of malformed and invalid HTML because the internet is the wild west of bad code.

In this course we expect you to write valid HTML. Once we start adding JavaScript to our web pages later in the course, it will become much more important for the HTML to be correct, so get into the habit of checking for, and fixing your validation errors now.

We will fix (and explain) the 4 issues in this order:

1. Missing the “DOCTYPE” declaration (#3)
2. Missing the Element “head” (#4)
3. Missing the “lang” attribute (#1)
4. Missing the character encoding declaration (#2)

The missing DOCTYPE declaration is the easiest issues to resolve.

The first line of a script file file often describes how the rest of the file should be interpreted. For example, the first line of a Python script is usually a shebang. Something like this:

#!/usr/bin/env python3

print("hello World! 🐍")

The shebang is not executable Python code, its metadata which informs anyone/anything reading the file that it is a Python script, specifically Python 3. In HTML, the first line should always be the DOCTYPE declaration, and it looks like this:

<!DOCTYPE html>
<html>
    <body>
        <h1>Hello World! 😃</h1>
    </body>
</html>

📝 Task 4: Declare the DOCTYPE

Add the HTML DOCTYPE declaration to your hello_world.html file.

✅ HTML versions

The following DOCTYPE declaration is HTML5

<!DOCTYPE html>

HTML5 became an official W3C recommendation in late 2014. However, if for some reason you need to develop a website in HTML4 (there is no real reason that you would ever need to do this unless you needed to support some ancient web browsers from 10 years ago), then you would use a more complicated DOCTYPE declaration:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

Everything in COSC203 will be using HTML5, so use the HTML5 DOCTYPE.

HTML documents are made out of elements. HTML elements are defined with opening and closing tags. Tags are keywords enclosed within “angle brackets” <>.

For a paragraph of text we use a paragraph element, which begins with the opening tag <p> and ends with the closing tag </p> (note the / in the closing tag).

If we refer back to our hello world example again we can see 3 elements, defined by 6 tags (html, body, and h1). These three elements overlap each other, in a way we call nested, like the Russian Matryoshka Doll 🪆🪆🪆

<!DOCTYPE html>
<html>
    <body>
        <h1>Hello World! 😃</h1>
    </body>
</html>

These three elements are:

• <html> ... </html> defines the root HTML document.
• <body> ... </body> defines the body of the HTML document.
• <h1> ... </h1> defines a heading. Also known as “heading level 1”.

The following diagram shows our 3 nested elements as a Box Model. Where h1 is inside body, and body is inside html.

flowchart TD
    subgraph html
        subgraph body
            direction LR
            subgraph h1
                text2["Hello World! 😃"]
            end
        end
    end
style html fill:#ff03,stroke-width:2px,stroke:#333
style body fill:#4186c988,stroke-width:2px,stroke:#333
style h1 fill:#4186c988,stroke-width:2px,stroke:#333
style text2 stroke:#333,stroke-width:1px

✅ Indentation

In HTML, Indentation is optional. Using white space can help show the nested structure, but it doesn’t change how the document will be rendered.

For example, this:

<!DOCTYPE html><html><body><h1>Hello World! 😃</h1></body></html>

and this:

<!DOCTYPE html>
<html>
<body>
<h1>Hello World! 😃</h1>
</body>
</html>

… are both the same as our first hello world.

Let’s fix the missing head element issues. And also give our document a title at the same time.

Along with the DOCTYPE declaration, there are 3 more things every HTML file requires:

1. html is the root of the HTML document
   • everything must be contained within the root
2. head is the document’s metadata
   • extra information like: title, author, style, encoding, scripts, …
3. body is the required element for the document content
   • the actual content of the document (paragraphs, images, etc…)

flowchart
	subgraph html
		direction LR
		subgraph head
			text1["document meta data here"]
		end
		subgraph body
			text2["document content here"]
		end
	end
style html fill:#ff03,stroke-width:2px,stroke:#333
style body fill:#4186c988,stroke-width:2px,stroke:#333
style head fill:#4186c988,stroke-width:2px,stroke:#333
style text1 fill:#0000,stroke:#3338,stroke-width:2px,stroke-dasharray:10
style text2 fill:#0000,stroke:#3338,stroke-width:2px,stroke-dasharray:10

📝 Task 5: Declare the HTML elements head and title

1. Insert a <head></head> element to your .html file.
   • head belongs inside html but outside body.
   • head comes before body.
2. Insert a <title></title> element inside head
3. Give your document a title
   • by inserting text within the title element.

The Box Model of our document should now look something like this:

flowchart TD
	subgraph html
        direction LR
        subgraph head
            subgraph title
                text1["my custom title :-)"]
            end
        end
        subgraph body
            direction LR
            subgraph h1
                text2["Hellow World! 😃"]
            end
        end
    end
style html fill:#ff03,stroke-width:2px,stroke:#333
style head fill:#4186c988,stroke-width:2px,stroke:#333
style title fill:#4186c988,stroke-width:2px,stroke:#333
style body fill:#4186c988,stroke-width:2px,stroke:#333
style h1 fill:#4186c988,stroke-width:2px,stroke:#333
style text1 stroke:#333,stroke-width:1px
style text2 stroke:#333,stroke-width:1px

A web browser should now render your custom title in the window tab.

Let’s fix the emoji next!

HTML attributes add extra information for elements. Attributes always appear in the opening tag (never in the closing tag). Attributes are defined in name="value" pairs.

It is good practice to use the lang attribute to declare the language your web page is written in.

Declaring the language (e.g. English / Te Reo) can help the web browser to render the document. For example, some languages render text from right-to-left. Declaring the language is also basic Search Engine Optimization (SEO). If a Search Engine knows the language a document is written in, it will show the document only to people who speak that language.

<html lang="en">

<html lang="en-nz">

<html lang="mi">

✅ Multi-Lingual HTML Documents

If an HTML document needs to support several languages, you may set the lang attribute on specific elements.

<body>
    <h1 lang="en">hello everyone 👋</h1>
    <h1 lang="mi">Kia ora tātou 👋</h1>
    <h1 lang="sm">Talofa tagata uma 👋</h1>
    <h1 lang="zh-cn">大家好 👋</h1>
</body>

📝 Task 6: Declare the lang attribute

Declare the language of your HTML document.

1. Give your <html> tag a lang attribute
2. Set the attribute to "en", "en-nz", or "mi"

Unicode is an international standard for text and emoji characters. UTF-8 encoding is the most popular implementation of Unicode because it is backwards compatible with older encoding implementations like ASCII. If we declare UTF-8 our emoji should render correctly in all web browsers that support UTF-8 (which is all modern browsers).

✅ Unicode and UTF-8

If you would like to learn more about UTF-8 watch Tom Scott talking about UTF-8 here.

📝 Task 7: Declare the charset encoding

Declare your document’s character set as UTF-8 encoding.

1. Insert a <meta> tag inside your head element.
2. Give your <meta> element a charset attribute.
3. Set the charset attribute to "UTF-8".

<head>
	<meta charset="UTF-8">
</head>

✅ Tip

The <meta> element is special as it requires only 1 tag, a self-closing tag. We call these Empty Elements. Another Empty Element is <img> for the Image Element.

The Box Model of your document should now look something like this:

flowchart TD
    subgraph html
        l(["lang=“en”"])
        direction LR
        subgraph head
            direction LR
            subgraph title
                direction TB
                text1["my custom title :-)"]
            end
			subgraph meta
                c(["charset=“UTF-8”"])
            end
        end
        subgraph body
            direction LR
            subgraph h1
                text2["Hellow World! 😃"]
            end
        end
    end
    style c fill:#f79,stroke:#333,stroke-width:2px
    style l fill:#f79,stroke:#333,stroke-width:2px
    style html fill:#ff03,stroke-width:2px,stroke:#333
    style head fill:#4186c988,stroke-width:2px,stroke:#333
    style meta fill:#4186c988,stroke-width:2px,stroke:#333
    style title fill:#4186c988,stroke-width:2px,stroke:#333
    style body fill:#4186c988,stroke-width:2px,stroke:#333
    style h1 fill:#4186c988,stroke-width:2px,stroke:#333
    style text1 stroke:#333,stroke-width:1px
    style text2 stroke:#333,stroke-width:1px

Semantic Elements provide structure to HTML documents. Building web pages with them helps with both accessibility browsers (e.g. screen readers for the sight impaired), and also SEO. If a search engine can better understand the structure of your web page, it can extract better information.

Let’s build a bigger web page with several of these semantic elements.

📝 Task 8: Create index.html

Use what you have learned so far to create an HTML5 file using Blueprint below.

1. Create a new file called index.html
2. Insert
   • HTML doctype
   • tags for the html element
   • tags for the head and body elements (inside html)
3. Insert the following semantic elements (inside body)
   • header
   • nav
   • main
   • footer
4. Insert the rest of the tags/attributes/text from the Blueprint below.
   • The <img> element needs the file: polly.jpg saved into the same directory as index.html
5. Upload index.html to the W3C Validator
   • ensure it reports 0 errors and 0 warnings

Each element in this blueprint is explained in the table beneath.

flowchart TD
    subgraph html
        l(["lang=“en”"])
        direction LR
        subgraph head
            subgraph meta
                c(["charset=“UTF-8”"])
            end
            subgraph title
                direction TB
                text1["Polly's Travel Blog"]
            end
        end
        subgraph body
            direction LR
             subgraph header
                subgraph h1
                    text2["Polly's Travel Blog"]
                end
            end
            subgraph nav
                direction LR
                subgraph navTitle["h2"]
                    Navigation
                end
                subgraph ul
                    subgraph navList1["li"]
                        subgraph navLink1["a"]
                            direction LR
                            href1(["href=“index.html”"])
                            navName1["Home"]
                        end
                    end
                    subgraph navList2["li"]
                        subgraph navLink2["a"]
                            href2(["href=“stories.html”"])
                            navName2["Stories"]
                        end
                    end
                    subgraph navList3["li"]
                        subgraph navLink3["a"]
                            href3(["href=“contact.html”"])
                            navName3["Contact"]
                        end
                    end
                end
            end
			subgraph main
				subgraph section
					direction LR
					subgraph sectionHeader["h2"]
						text4["Polly the Penguin 🐧"]
					end
					subgraph img
                        direction LR
						src(["src=“polly.jpg”"])
                        alt(["alt=“Photo of Polly”"])
					end
					subgraph sectionP["p"]
						text5["Stories about my life as a penguin!"]
					end
				end
				subgraph section2["section"]
					subgraph articleHeader["h2"]
						text6["Leaving Home"]
					end
					subgraph articleP["p"]
						text7["Today I travel for Antarctica!"]
					end
                    subgraph articleP2["p"]
						text8["I will bring my favourite scarf."]
					end
				end
			end
            subgraph footer
                subgraph footerLink["p"]
                        text3["© Copyright 2022 by Polly. No rights reversed."]
                end
            end
        end
    end
    style l fill:#f79,stroke:#333,stroke-width:2px
    style c fill:#f79,stroke:#333,stroke-width:2px
    style href1 fill:#f79,stroke:#333,stroke-width:2px
    style href2 fill:#f79,stroke:#333,stroke-width:2px
    style href3 fill:#f79,stroke:#333,stroke-width:2px
    style src fill:#f79,stroke:#333,stroke-width:2px
    style alt fill:#f79,stroke:#333,stroke-width:2px
    style html  fill:#ff03,stroke-width:2px,stroke:#333
    style head  fill:#4186c955,stroke-width:2px,stroke:#333
    style meta  fill:#4186c955,stroke-width:2px,stroke:#333
    style title fill:#4186c955,stroke-width:2px,stroke:#333
    style body fill:#4186c955,stroke-width:2px,stroke:#333
    style header fill:#4186c955,stroke-width:2px,stroke:#333
    style h1 fill:#4186c955,stroke-width:2px,stroke:#333
    style nav fill:#4186c955,stroke-width:2px,stroke:#333
    style navTitle fill:#4186c955,stroke-width:2px,stroke:#333
    style ul fill:#4186c955,stroke-width:2px,stroke:#333
    style navList1 fill:#4186c955,stroke-width:2px,stroke:#333
    style navLink1 fill:#4186c955,stroke-width:2px,stroke:#333
    style navList2 fill:#4186c955,stroke-width:2px,stroke:#333
    style navLink2 fill:#4186c955,stroke-width:2px,stroke:#333
    style navList3 fill:#4186c955,stroke-width:2px,stroke:#333
    style navLink3 fill:#4186c955,stroke-width:2px,stroke:#333
    style sectionHeader fill:#4186c955,stroke-width:2px,stroke:#333
    style img fill:#4186c955,stroke-width:2px,stroke:#333
    style sectionP fill:#4186c955,stroke-width:2px,stroke:#333
    style articleP2 fill:#4186c955,stroke-width:2px,stroke:#333
    style articleHeader fill:#4186c955,stroke-width:2px,stroke:#333
    style articleP fill:#4186c955,stroke-width:2px,stroke:#333
    style footerLink fill:#4186c955,stroke-width:2px,stroke:#333
    style section fill:#4186c955,stroke-width:2px,stroke:#333
	style main fill:#4186c955,stroke-width:2px,stroke:#333
    style section2 fill:#4186c955,stroke-width:2px,stroke:#333
    style footer fill:#4186c955,stroke-width:2px,stroke:#333
    style text1 stroke:#333,stroke-width:1px
    style text2 stroke:#333,stroke-width:1px
    style text3 stroke:#333,stroke-width:1px
    style text4 stroke:#333,stroke-width:1px
    style text5 stroke:#333,stroke-width:1px
    style text6 stroke:#333,stroke-width:1px
    style text7 stroke:#333,stroke-width:1px
    style text8 stroke:#333,stroke-width:1px

The below tables lists the elements we have seen so far.

For a full reference of HTML elements, check the Mozilla web docs.

✅ Image Element

The Image Element has a few special characteristics.

<img src="url/filename.jpg" alt="Description of the image">

• The img element uses a self-closing tag (like the meta element). This means that you don’t need to add a closing tag yourself.
• The src attribute is a URL, which points to the image source.
  • The URL Could point to anywhere on the internet (hot linking)
  • Or, it could point to a local file, with an absolute or relative path.
• The alt attribute is an alternative description of the image.
  • for SEO and accessibility browsers (e.g. screen readers).

Web links or hyperlinks are an important concept for the web. They allow us to link HTML pages together to create an interconnected web of pages.

In HTML, hyperlinks are created with Anchor Elements with the <a> tag. Clicking on an anchor element will load that HTML page.

Below are two examples of hyperlinks, the first has a relative URL that links a local HTML document, the second has an absolute URL that links to another website.

<a href="contact.html">Click Me!</a>
<a href="https://google.com">Google</a>

An anchor tag does nothing without the href attribute (hyperlink reference). The value of the href attribute is the destination we want our link to go, which is either a relative URL or an absolute URL.

📝 Task 9: Create a multi-page site

In this task we will create a multi-page site.

1. Start with index.html from the previous task(s).
2. Create 2 copies in the same directory
   • stories.html
   • contact.html
3. Change the h1 element(s) of each page to something more descriptive
   • html > body > header > h1
4. Change the main content of the 2 new pages to something else
   • html > body > main
5. For anchor elements that link to their own page, change the href to "#!"
6. Test your sites page navigation by clicking the hyperlinks in the <nav> element

✅ Tip

The hash value "#" in a href indicates a URL fragment and is used to link directly to a specific element within a page.

For example, the below link uses the URL fragment #Examples so clicking the link will open the page and scroll down to the Example section on the page.

https://en.wikipedia.org/wiki/URI_fragment#Examples

<a href=https://en.wikipedia.org/wiki/URI_fragment#Examples>https://en.wikipedia.org/wiki/URI_fragment#Examples<a>

Using the href value #! is standard practice to link nowhere.

Along with HTML documents, anchor tags can link to various different resource files on the internet. The href URL may refer to: images, videos, audio, zip files etc. Modern web browsers will open many file types (images, video, pdf, etc.) but if the resource file is not supported, clicking the link will simply download file, the default behaviour.

<a href="polly.jpg">an image</a>
<a href="data.zip">a download</a>

Note — these links will result in 404 errors pages since the files that the links point to don’t exist.

Absolute URLs begin with the protocol e.g https: in https://www.google.com/. The protocol tells the web browser how to retrieve the page. The 3 most common are https:, http:, and ftp:.

There are also Resource Schemes which are very similar, the two we will look at are mailto: and tel: Which identify an email address and a phone number respectively.

<a href="mailto:name@mail.nz" >email</a>
<a href="tel:+64034798397" >phone</a>

Clicking the above links on a smart phone should open an email app or phone app.

📝 Task 10: Create some contact links

1. Create 3 anchor elements in the contact.html page
   • Somewhere in html > body > main > section
2. Make one link to another website with https:
3. Make one link to an email address with mailto:
4. Make one link to a telephone number with tel:

✅ Tip

The anchor element may also have a target attribute, which specifies where to open the link. In the current window or in a new window/tab.

<a target="_self" href="https://google.com/" >open in this window</a>

<a target="_blank" href="https://google.com/" >open in a new window or tab</a>

Last section! 🎉

Writing HTML can be tiresome which is why Emmet was created. Emmet is like auto complete for HTML, and Visual Studio Code has Emmet built in.

Let’s start off by generating some HTML boilerplate with Emmet. If you open a blank file in VS Code (with a .html extension) and type !, it will trigger an Emmet Abbreviation.

Pressing enter will generate the following HTML boilerplate:

That is just 1 of many Emmet abbreviations. There are 3 other abbreviations you may find useful:

• > creates a child element
• + creates a sibling element
• * creates multiple elements

You can chain these abbreviations together in order to create a complex structure of HTML elements. To understand what that all means you could read the Emmet documentation, or watch the demonstration video below which finishes the previous lab exercise in less than a minute!

Below are the Emmet abbreviations used in the above demo.

• !!!
• html>head+body
• header>h1
• nav>ul>li*3>a
• main>section>h2+img+p
• section>h2+p*3
• footer>p
• meta[charset=UTF-8]

✅ Emmet Cheat Sheet

If you want to become a Emmet power user read this cheat sheet: https://docs.emmet.io/cheat-sheet/

(or at the very least bookmark it for later)

📝 Task 11: Try out Emmet

1. Test out Emmet
   • try the single exclamation mark: !
   • try the triple exclamation mark !!!
2. Recreate index.html using Emmet abbreviations
3. Can you recreate index.html with a single Emmet abbreviation?

• Task 1: Get Visual Studio Code running
• Task 2: Hello World in HTML
• Task 3: Validate helloworld.html
• Task 4: Declare the DOCTYPE
• Task 5: Declare the HTML elements head and title
• Task 6: Declare the lang attribute
• Task 7: Declare the charset encoding
• Task 8: Create index.html
• Task 9: Create a multi-page site
• Task 10: Create some contact links
• Task 11: Try out Emmet