In this exercise, you’ll develop an application that calculates the sales tax and invoice total after the user enters the subtotal and tax rate.
computer science
Description
Total:
40 points
All
assignments should be individual work. Discussion with class mates is allowed
but the final code has to be written individually. If you take code from any
Web site, provide the links in your submission files.
All
the files you need for this exercise are available on Canvas->Course Schedule->A2.zip
Start early.
DO NOT USE jQuery or CSS to implement the programs. You can
use CSS only for styling purposes. Solutions should be general enough so that
if the size or content of arrays changes, your code will still work.
1.
(10) In this exercise,
you’ll develop an application that calculates the sales tax and invoice total
after the user enters the subtotal and tax rate.
a)
Open the HTML and
JavaScript files provided in the folder sales_tax
b) Then,
run the application to see the user interface shown above, although that
interface won’t do anything until you develop the JavaScript for it.
c)
In the JavaScript file,
write the code for calculating and displaying the sales tax and invoice total
when the user clicks on the Calculate button.
d)
Add the JavaScript event
handler for the click event of the Clear button. This should clear all text
boxes.
e)
If you haven’t already done
so, add data validation to this application. The subtotal entry should be a valid,
positive number that’s less than 20,000. The tax rate should be a valid, positive
number that’s less than 10. The error messages should be displayed with span
tags, and the error messages should be:
Must be
a positive number less than 20,000
Must be a positive number less than 10
f)
Add JavaScript code that
focuses the cursor to the Subtotal field when the application starts and when
the user clicks on the Calculate button.
2.
(10) In this exercise, you
start with the declarations for two arrays, a names array and a scores array. Then
you will add one button that will display the scores and another button that
will calculate and display the average score.
