Glossary

Glossary

A collection of terms and their definitions encountered during the workshop.

JavaScript

Statement

• A statement is a complete instruction for the browser/UA to complete.
• The end of a statement is marked with a semicolon.
• The semicolon is part of the JS language syntax.
• Syntax is the set of rules that describe how a language is written.

Expression

Code block

• Code blocks are defined by a pair of curly braces. Statements listed between open and closed curly braces.

Operator

• Operators are symbols or keywords JS uses to evaluate or manipulate data. We’ll take a closer look at operators later.
• Assignment operator
  • The = sign, roughly in the middle of the statement, is called the ‘assignment operator’
  • The assignment operator is one of many operators in the JS language, also part of the syntax

Case sensitivity

White space

Comment

Literal

String

• Strings are one of three primitive data types in JS. Numbers and booleans (true/false) are the other two.
• Strings are characters captured between a pair of double quotes or a pair of single quotes.
  • Like letter beads strung on a string.
• They’re sort of like atoms or “primary” colors. The primitive data types can’t be made from anything else.

Variable

• A variable is a means of storing a piece of data in memory and giving it a name so we can refer to it elsewhere in the program.
• The var keyword tells JS that we are creating a variable. We declare the variable to JS.
• The variable name is a unique identifier with some syntax rules.
  • a-z, A-Z, 0-9
  • _, $ allowed
  • dashes not appreciated
  • First character must be a letter or $
  • Case sensitive
• Where ever we need the data in the variable, we insert the variable name.

Constant

Identifier

Semicolon (;)

API

Document Object Model

Loop

Branch

Function

• A function is a block of code written once and stored in memory while the program is running.
  • Functions are declared using the function keyword, frequently followed by the name of the function.
    • Naming rules same as for variables
  • Functions can receive data values for use within the function and can return data back to where the function was called.
  • Code blocks are defined by a pair of curly braces. Statements listed between open and closed curly braces.

Event

• An event is an action, usually triggered by the user: mouse click, key press, focus on a link or form element, loading a page.

Event handler

• An event handler is an instruction to JS to ‘listen’ for a particular event to happen. JS has further instructions for what to do when it ‘hears’ the event happen.