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.
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"
Debugging
Finding and fixing problems in an algorithm or program.
Equality operator
Comparison/logical operator: evaluates to true when the operands have the same value.
Event
An action that causes something to happen.
Event handling
an overarching term for the coding tasks involved in making a program respond to events by triggering functions.
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.
Event-driven program
a program designed to run blocks of code or functions in response to specified events (e.g. a mouse click)
Expression
Any valid unit of code that resolves to a value.
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.
If-Statement
The common programming structure that implements "conditional statements".
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.
UI Elements
on-screen objects, like buttons, images, text boxes, pull down menus, screens and so on.
User Interface
The visual elements of a program through which a user controls or communicates with the application. Often abbreviated UI.
Variable
A placeholder for a piece of information that can change.