In JavaScript, var and let are used to declare variables, but they have some key differences in terms of scope and hoisting.

• var: Variables declared with var are function-scoped. This means that they are only visible within the function in which they are declared. If a variable is declared outside of any function, it becomes a global variable.
• let: Variables declared with let are block-scoped. This means that they are only visible within the block (enclosed by curly braces) in which they are defined. This includes if statements, loops, and other block structures.

// Example with var
function exampleVar() {
  if (true) {
    var x = 10;
  }
  console.log(x); // Outputs 10, even though x was declared inside the if block
}

// Example with let
function exampleLet() {
  if (true) {
    let y = 20;
  }
  console.log(y); // ReferenceError: y is not defined
}

In the exampleVar function, x is accessible outside the if block due to var being function-scoped and hoisted. In the exampleLet function, trying to access y outside the if block results in a ReferenceError because let is block-scoped, and y is not accessible outside the block.