Block Scope

Block scope in JavaScript refers to the region of code enclosed by curly braces {}. Variables declared using let and const keywords within a block are limited to that block scope.

Example: 

function blockFunction() {
    if (true) {
        let letVariable = "letVaule";
        const constVariable = "constVaule";
        console.log(letVariable); // Accessing block-scoped variable
        console.log(constVariable); // Accessing constant block-scoped variable
    }

    console.log(letVariable); // not accessible
    console.log(constVariable); // not accessible
}

blockFunction();

In this example, letVariable and constVariable are only accessible in if block not outside of if block.