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<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>javascript uses of global variable</title> </head> <body> <script> // Global variable var counter = 0; // A function dedicated to manipulate the 'counter' variable function makeCounter() { return counter += 1; } // Calling the function makeCounter(); document.write(counter); // Prints: 1 document.write("<br>"); makeCounter(); document.write(counter); // Prints: 2 document.write("<br>"); // Trying to manipulate the 'counter' variable from outside counter = 10; document.write(counter); // Prints: 10 </script> </body> </html>