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What is the difference between let and var in JavaScript?

Asked on Mar 18, 2026

Answer

In JavaScript, "let" and "var" are both used to declare variables, but they have different scoping rules and behaviors. "let" is block-scoped, while "var" is function-scoped.
// Example of 'let' and 'var' scope

        function testScope() {
            if (true) {
                let blockScoped = "I am block scoped";
                var functionScoped = "I am function scoped";
            }
            console.log(functionScoped); // Works fine
            console.log(blockScoped);    // ReferenceError: blockScoped is not defined
        }

        testScope();
Additional Comment:
  • "let" is block-scoped, meaning it is only accessible within the block it is defined in.
  • "var" is function-scoped, meaning it is accessible throughout the function it is declared in.
  • Using "let" helps prevent errors due to variable hoisting and unintended variable reassignments.
  • "let" is generally preferred in modern JavaScript for its predictable scoping behavior.
✅ Answered with JavaScript best practices.
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