Your job is to make a half-plus-seven calculator.
Someone enters their age, and you tell them the youngest and the oldest that comport with the half-plus-seven rule.
Steps:

1. Make an HTML form with three input files, named age, min, and max
2. Make a JavaScript function that is run when the age field changes (maybe use onkeyup, or onchange)
3. Have that function fill in the min field, with 1/2 * age + 7
4. If the min field is under 18, replace the number with some warning
5. Have that function fill in the max field with (age-7)*2
6. If the max field is under 18, replace the number with some warning
7. If the entered age is less than 18, change the background with something suitable.
8. If the entered age is more than 50, change the background to something suitable.
9. Hard Ones
   1. Make a sound then they offer bad input
   2. Make a marquee appear and disappear based on input correctness
   3. Something funny

Sample form to work from.
Due: Mon Oct 23rd