A computer program is a list of "instructions" to be "executed" by the computer.
In a programming language, these program instructions are called statements.
Values, Operators, Expressions, Keywords, and Comments.
Fixed values are called literals. Variable values are called variables.
The most important rules for writing fixed values are:
Numbers are written with or without decimals:
Strings are text, written within double or single quotes:
Expressions can also represent fixed values:
In a programming language, variables are used to store data values.
An equal sign is used to assign values to variables.
In this example, x is defined as a variable. Then, x is assigned (given) the value 6:
The var keyword tells the browser to create a new variable:
Code after double slashes // or between /* and */ is treated as a comment.
Comments are ignored, and will not be executed:
The variables lastName and lastname, are two different variables.
Historically, programmers have used three ways of joining multiple words into one variable name:
first-name, last-name, master-card, inter-city.
first_name, last_name, master_card, inter_city.
FirstName, LastName, MasterCard, InterCity.
firstName, lastName, masterCard, interCity.
Unicode covers (almost) all the characters, punctuations, and symbols in the world.
For a closer look, please study our Complete Unicode Reference.