This counter uses a global variable to keep track of the current number.
It appears to work well. Try it and see...
There is a problem with using a global variable however. The problem is that any script on the page can change the global count variable.
See what happens when the wrong script affects the counter...
A closure is when there is a function within a function. The inner function has access to the outer function's variables. There are no other functions that have access to these variables.
This counter uses a closure which simulates a private variable
This doubling counter also uses a closure which simulates a private variable
This calculator has an outer function which receives an operator as a parameter and has an inner function (which does the calculation) that receives two operands as parameters.