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<!DOCTYPE html>
<html>
<body>
​
<h2>JavaScript Functions</h2>
<p>A function can access variables defined outside the function:</p>
​
<p id="demo"></p>
​
<script>
let a = 4;
myFunction();
​
function myFunction() {
  document.getElementById("demo").innerHTML = a * a;
} 
</script>
​
</body>
</html>
​