HTML

• The head element contains information about the webpage
• The body element represents the visible content shown to the user
• When working with visible HTML elements, you must always use opening and closing tags
• Child elements are nestled inside other elements
• Parent elements hold the child elements
• Semantic elements have a name that describes its content and role, which makes code easier to read
• A header appears at the top and usually contains a navigation menu and/or introductory content
• When using headings, its important to use in order from h1 to h6. The biggest heading, h1, should only appear once
• A footer goes at the bottom, usually contains the author, copyright, contact, sitemap and navigation
• A section, is a semantic element that defines sections in a document and allows organization of content based on topics
• h1-h6 defines level of heading
• p defines a paragraph or block of text
• ul defines an unordered list (bullets)
• ol defines an ordered list (numbered)
• li defines list items
• img defines information about images, src attribute defines location of image
• br defines a line of empty space, line break between two blocks of content
• a is for anchor, creates links. href attribute points to URL for link

CSS

• A margin indicates how much space we want around the outside of an element
• A padding indicates how much space we want around the content inside an element
• Inline style sheet: styles apply directly to specific element, good for quick and permanent changes, less flexible since each inline style must be edited when making changes
• Internal style sheet: embeded directly into HTML file, style element in head element, rules apply only to that page, single change to CSS rule will apply to all tagged elements
• External style sheet: most common, can keep all CSS rules in separate file, making changes easier. Link file using link element in HTMLs head element
• rel= defines relationship between style sheet and html
• Separation of concerns: separating code into different files based on use. Each section of code should have its own responsibility
• CSS rule is structured with a selector and declaration block, declaration block has declarations made of properties and their values
• A selector defines elements or attributes to which rules/declarations apply
• A * selector indicates that all elements on a page will have the same style properties
• You can combine two selectors with a comma, allowing declaration to affect both selectors, such as header, footer
• DRY code: Do Not Reapeat Yourself code, 2 or more elements that will share the same styling can be grouped together. This reduces the number of lines of code and size and complexity
• text-align: postion property, a way to centre title/heading, can also apply to images
• display:block : assigns each image to start on a new line
• class attribute as selector, adds styles to certain elements of choice, but not all.
• colours can be added by semantic references or hexadecimal code, or hex#

Git

• git status: checks what branch we are currently on
• git checkout -b branch-name: creates a new branch and switches to it
• git checkout main: takes you back to main branch
• git add -A: adds modification in current working branch to staging area. -A indicates we want to add all changes
• staging area informs Git that the changes will be added in next commit
• git commit -m: commit command with message that describes what commit contains
• git pull: receive a branch's modifications into local environment
• git pull origin: the source pull will be from the GitHub repo
• git pull origin main: indicates main branch will be pulled from GitHub repo
• git push: pushes changes from local environment to remote GitHub
• git push origin feature/branch-name: pushes changes we have locally to remote Github branch in repo, or creates new branch

JavaScript

• A variable is a named container that allows us to store data in our code.
• Control flow is the order in which a computer executes code in a script.
• Code is read and executed from top to bottom of page
• To declare a variable use var, give it a unique name, then assign operator = to assign specific data we want to store.
• console.log method is used to output a message to the web console by adding an argument.
• console refers to a test environment that developers use to check code.
• .log is a method, a set of instructions to be executed.
• if statement can interrput the control flow. It's a conditional statement. Conditional statements test if expression is true or not.
• You can have more than one conditional statement by using else if.
• All values considered truthy except for: 0, -0, On, "", null, undefined, NaN, or Boolean data type with value of false.
• An Array is a stored group of related data, represented by a single variable. They are zero-indexed and sequential.
• Index is a unique number that identifies the location of a piece of data.
• A for loop uses a predictable pattern of indices to perform a task on all items in an array, by allowing a single code block to be executed repeatedly.
• You can comment out code by using /* before and */ after a block of code.
• A function is a set of instructions that tell the computer how to perform a certain task. They do not automatically execute and need to be called by name.
• JavaScript allows users to interact with a website.
• A semi colon at the end of a line indicates the end, is required when separating statements, but is good practise to use after every statement.
• The varaible types are: string, number, boolean, array, and object.
• Operators are mathematical symbols that produce results based on two values/variables.
• Operator types are: addition, subtraction, multiplication, division, assignment, strict equality, and Not, Does-not-equal.
• Events are code structures that listen for activity, and run code in response. Example: click event is fired by browser wen you click on something.
• Data types: null, undefined, Boolean, number, BigInt, string, and symbol.
• JSON (JavaScript Object Notation): lightweight data-interchange format, derived from JavaScript, used by many programming languages. It builds universal/transferable data structures.