Variables

Variables Variables provide a way for us to store a value that we can modify and use throughout a program.

A variables can be considered a named memory container where the programmer can store values that will be changing in their programs.

To create a variable in javascript, we use the keyword var, followed by the name that we'll use as a label to access that value, this is referred to as declaring a variable.

  `var mySpecialValue;  //declare a variable ` 

This varible-name acts as a label to identify an area in the computer's memory where the value will be stored, so the programmer can access and modify the value throughout the program.

Declare and initialize a variable:

    var mySpecialValue;  //declare a variable
    mySpecialValue=5;  //assign a value of 5
    mySpecialValue = 15 * 2; //re-assign a new value to the variable

The first line of code above, creates a variable by declaring the keyword: var, followed by the identifier name mySpecialValue.

In the next statement, we assigns the value 5 to the variable. The third line of code changes the value stored in the memory location: mySpecialValue to the result of the evaluation of the expression: 15 * 2.

Variable Types

Javascript in a loosely-typed programming language. The type of a variable is determined dynamically, based on the value currently assigned to the variable. A variable can be assigned different types of values throughout a program. This is in contrast to most other programming languages like Java or C++, which are strongly-typed. In strongly-typed languages, when we want to declare a variable, we must first specify the data-type that we want to use.

Dynamically determined variable type:

var mySpecialValue = 5;   //assigned a numeric type
mySpecialValue="hello";   //a string has now been assigned to the same variable