Arithmetic

This online wine order form uses Math methods to calculate a total and convert the result to dollars and cents. Here's the source code. Observe:

• the Math.floor() method -- truncates the fractional part of a number (e.g. converts 3.6 to 3)
• the Math.round() method -- rounds to the nearest integer (e.g. converts 3.6 to 4)

• Math.exp() -- Returns e^number, where number is the argument, and e is Euler's constant, the base of the natural logarithms.
• Math.log() -- Returns the natural logarithm (base e) of a number.
• Math.max() -- Returns the greater of two numbers.
• Math.min() -- Returns the lesser of two numbers.
• Math.pow() -- Returns base to the exponent power, that is, base^exponent.
• Math.random() -- Returns a pseudo-random number between 0 and 1.
• Math.sin() -- Returns the sine of a number.
• Math.sqrt() -- Returns the square root of a number.
• Math.tan() -- Returns the tangent of a number.

Lab

Your task:

• Copy the example program and add to it the following feature.
• Calculate the tax and add another text field to display it.
• Don't forget to add it to the total amount!
• Hint: Use our moneyFormat() function.

Solution

Don't peek unless you're stuck!

• Run it.
• Source code.

Extra for Experts

• Instead of waiting for the user to click Place Order, recalculate the total whenever a field's value is changed.
• Solution
• Source code