1. Variables are fundamental building blocks in a programming language, its a data item that represents a memory location on the computer.
2. Variables are similar to containers that can contain hold data items like numbers and string. Variables have a name, value and type
3. Values assigned to variables can change throughout the course of the program, while the values of literals remain constant.
3. Three types of data can be assigned to the variables.
1. There exists some rules for assigning valid names for variables.
2. The first character of a variable must be letter or an underscore(_) or dollar($)
2. Values can be assigned to variables after initialization, though not mandatory.If the variable is declared but not initialized its called as "undefined".
Local : Local variables are declared within a function, they are private to the function and can be accessed from only within the function
1. In order to concatenate variables the operator + is used. Addition is performed when both the operands are numbers.
2. Incase, the expressions involved are both numberic and string, then to perform the addition operation, numeric values are converted to string .