CISC103, Fall 2006

lab06: Simple calculations with JavaScript

Introduction

This lab is different from ones you have done so far. In this lab, you'll be

• given a sample problem, and a solution to that problem.
• given a similar problem, and asked to come up with your own solution.

The solved problem is this: write a web page that allows a user to determine the price-per-square-inch of a pizza of a given diameter and price.

The problem where you will come up with your own solution is to determine the gas mileage of a car, given the starting odometer reading, the ending odometer reading, and the number of gallons of gas consumed in between the two odometer readings.

Learning objectives

By the time you complete this lab, you should know how to do the following in JavaScript:

• prompt for values using window.prompt()
• convert values to numeric data using both parseInt() and parseFloat()
• do simple calculations using assignment statements
• print out the results to the screen using document.write()

You should also know how to put JavaScript into an HTML file that will pass validation at validator.w3.org.

Step-by-Step Instructions

Step 1: Look over the pizza.html web page

Here is the assignment for the file pizza.html. Read over this assignment, then look at the solved problem in the file pizza.html (located in the folder lab06 under the labs on the course web page.)

radius = diameter / 2;

radius * radius

Try reloading the page several times. Also do a "view source" and read through and try to understand the HTML and JavaScript source. Finally, note that if you run this through validator.w3.org, it will pass validation as HTML 4.01 Transitional.

Step 2: Put the pizza.html file on your web site on copland

Your next step is to put this pizza.html file on your web site on copland, so that if you click on the link below (where your userid is in place of "userid"), the file comes up.

http://copland.udel.edu/~userid/cisc103/lab06/pizza.html

Here's what you need to do:

1. Download the file to the hard drive of your PC
2. Open the ssh secure file transfer program, and connect to copland.udel.edu.
3. On the copland side of the window, navigate into public_html, and create a folder called cisc103 (if it doesn't already exist). Navigate into that folder.
4. Now, inside cisc103 (which is inside public_html), create a folder called lab06
5. Upload the pizza.html file into the folder lab06.
6. Make sure that

   http://copland.udel.edu/~userid/cisc103/lab06/pizza.html
   
   links to the pizza.html page.
   
   Note: If you have trouble with errors such as "403 forbidden", then you need to right click on the file in the SSH File transfer program, and set the permissions of the file to the octal number "755". You may need to do this on the folders public_html, cisc103, and lab06 as well, if it was not already done.

7. When you have done this, you are ready to move on to steps 3 and 4. If you can't get it to work, you can move on to step 3 until you can get help from your TA or your instructor, but you won't be able to proceed to step 4 until you get this step to work.

Step 3: Write your own web page gas.html to calculate gas mileage

Now write a page similar to pizza.html called gas.html that solves the following problem. Save the file under a folder called lab06 under your personal folder on the H drive.

Note that in order for the JavaScript section to pass validation, you need to enclose it in an HTML comment, as shown in the example pizza.html.

Step 4: Upload gas.html to your web site on copland

Now, to submit the file, use the same process you used in step 2 to upload this file to the following URL:

http://copland.udel.edu/~userid/cisc103/lab06/gas.html

Due Date: Oct 19, 11:55pm

Evaluation and Grading

This activity counts as a regular lab grade out of 100 pts, broken down as follows:

Copyright 2006, Phillip T. Conrad, CIS Dept., University of Delaware. Permission to copy for non-commercial, non-profit, educational purposes granted, provided appropriate credit is given; all other rights reserved.