Postfix Notation Calculator

This calculator uses postfix notation, and works a little differently from calculators you may have used. Suppose you want to add two numbers. Enter the first number. Press "Enter." This commits the first number into the calculator's memory. Then enter the second number. After that, enter the type of operation (such as "+") that you wish to perform.
This is a sample of JavaScript in action. If you view the source (choose Document Source from the View menu), you'll see that a number of functions, written in JavaScript, are located in the header of this HTML file. These functions are used to perform various math and formatting operations on the client machine.