Variable scope refers to the accessibility and visibility of variables within different parts of a JavaScript program. In JavaScript, variables can have either global scope or local scope. Global scope variables are accessible from anywhere in the program, while local scope variables are only accessible within the function or block in which they are declared.
JavaScript uses lexical scoping, which means that the scope of a variable is determined by its location within the code. This allows for nested scopes, where a variable declared in an inner scope can shadow a variable with the same name in an outer scope. Understanding variable scope is important for writing maintainable and bug-free JavaScript code.
