JavaScriptEasy
Explain the difference between global scope, function scope, and block scope
By FrontendPro Editorial Team Updated 8/8/2026
#JavaScript
Answer
Global scope means variables are accessible from anywhere in the code. Function scope means variables are accessible only within the function they are declared in. Block scope means variables are accessible only within the block (e.g., within {}) they are declared in.
js
var globalVar = "I'm global"; // Global scope
function myFunction() {
var functionVar = "I'm in a function"; // Function scope
if (true) {
let blockVar = "I'm in a block"; // Block scope
console.log(blockVar); // Accessible here
}
// console.log(blockVar); // Uncaught ReferenceError: blockVar is not defined
}
// console.log(functionVar); // Uncaught ReferenceError: functionVar is not defined
myFunction();