Topics

#scope

1. 1. Scope defines the visibility or accessibility of a variable.

#We have Two scopes

1. 1. Global Scope
2. 2. Local Scope

#Global scope

1. 1. The variable declared in global scope can be accessed anywhere in the program.
2. 2. Global scope has the highest accessibility.
3. 3. Variable declared with var goes in Global scope.

#Local scope

1. 1. Local/block scope/function scope
2. 2. The variable declared in local scope can be accessed in that block only i.e. we can not access the variable from outside.
3. 3. JS engine creates local scope for functions and blocks.
4. 4.

   Function's Local Scope

   - Local scope created for function is refered as function scope.
   - Variable's declared in function's scope can not be accessed from outside.
5. 5.

   Block's Local Scope

   - Local scope created for block is refered as block scope.
   - Variable's declared in block scope can not be accessed from outside.
   - But only variables declared with var are accessible from outside of block.
   
   Note: Variables declared with let and const are also locally scoped.
   Firefox represent it as - Block scope.
   Chrome represent it as - Script scope.