Events
Callback function
a function specified as part of an event listener; it is written by the programmer but called by the system as the result of an event trigger.
Canvas
a user interface element to use in HTML/JavaScript which acts as a digital canvas, allowing the programmatic drawing and manipulation of pixels, basic shapes, figures and images.
Debugging
Debugging - Finding and fixing problems in an algorithm or program.
Event handling
an overarching term for the coding tasks involved in making a program respond to events by triggering functions.
Variable
A placeholder for a piece of information that can change.
Event
An action that causes something to happen.
UI Elements
on-screen objects, like buttons, images, text boxes, pull down menus, screens and so on.
Conditionals
Statements that only run under certain conditions.
If-Statement
The common programming structure that implements "conditional statements".
Expression
Expression - Any valid unit of code that resolves to a value.
Event-driven program
a program designed to run blocks of code or functions in response to specified events (e.g. a mouse click)
User Interface
The visual elements of a program through which a user controls or communicates with the application. Often abbreviated UI.
Local Variable
A variable with local scope is one that can only be seen, used and updated by code within the same scope. Typically this means the variable was declared (created) inside a function -- includes function parameter variables.
Concatenate
to link together or join. Typically used when joining together text Strings in programming (e.g. "Hello, "+name)
Data Type
All values in a programming language have a "type" - such as a Number, Boolean, or String - that dictates how the computer will interpret it. For example 7+5 is interpreted differently from "7"+"5"
Event handling
an overarching term for the coding tasks involved in making a program respond to events by triggering functions.
Return Value
A value sent back by a function to the place in the code where the function was called form - typically asking for value (e.g. getText(id)) or the result of a calculation or computation of some kind. Most programming languages have many built-in functions that return values, but you can also write your own.
Variable Scope
dictates what portions of the code can "see" or use a variable, typically derived from where the variable was first created. (See Global v. Local)
String
Any sequence of characters between quotation marks (ex: "hello", "42", "this is a string!").
Global Variable
A variable whose scope is "global" to the program, it can be used and updated by any part of the code. Its global scope is typically derived from the variable being declared (created) outside of any function, object, or method.
Event listener
a command that can be set up to trigger a function when a particular type of event occurs on a particular UI element.
Selection
A generic term for a type of programming statement (usually an if-statement) that uses a Boolean condition to determine, or select, whether or not to run a certain block of statements.
If-Statement
The common programming structure that implements "conditional statements"
Key Event
in JavaScript an event triggered by pressing or releasing a key on the keyboard. For example: "keyup" and "keydown" are event types you can specify. Use event.key - from the "event" parameter of the onEvent callback function - to figure out which key was pressed.
==
The equality operator (sometimes read: "equal equal") is used to compare two values, and returns a Boolean (true/false). Avoid confusion with the assignment operator "=",The equality operator (sometimes read: "equal equal") is used to compare two values, and returns a Boolean (true/false). Avoid confusion with the assignment operator "=",