How do closures work in Javascript

Question: What is closures?
Whenever you defined a the function within another function, the inner function has access to variables in the outer function.


Following are Simple example of closure.

function mainFunction(outerData) { var mainFuncData = 3; function innerFunction(innerFuncData) { console.log(outerData + innerFuncData + (++mainFuncData)); // will alert 16 } innerFunction(10); } mainFunction(7); //17 

Question: Why it can access to variables in the outer function?
Because It is defined as var , which means it is global variable.

Best Related Posts are Following:

1. Load multiple javascript files asynchronously.
2. Javascript Interview Questions and Answers for Experienced 2.
3. How do I copy to the clipboard in JavaScript.
4. Difference between encodeuri and encodeuricomponent in javascript.
5. What is difference between event.preventDefault() and return false in Javascript?.
6. What is the difference between call and apply in javascript?.
7. How to Include a JavaScript file in another JavaScript file?.
8. How can I get query string values in JavaScript and jQuery?.