​x
 
<!DOCTYPE html>
<html>
<body>
​
<h2>JavaScript Functions</h2>
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<p>Global functions automatically become window methods. Invoking myFunction() is the same as invoking window.myFunction().</p>
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<p id="demo"></p>
​
<script>
function myFunction(a, b) {
  return a * b;
}
document.getElementById("demo").innerHTML = window.myFunction(10, 2); 
</script>
​
</body>
</html>
​
​