Functions

Tools

JavaScript helper functions for cookie handling: cookie.js

XHTML to PDF translator: Prince 8.0 download.

Homework

Preliminary project pages due last Tuesday. Preliminary summary.pdf files due today.

Demonstration

Modify the convert.html page from last week to converts arbitrary decimal integers to hexidecimal Strings.

1. Respond to changes in the decimal field.
2. Complain, if the user enters something that is not a number.
3. Create a function to convert integers from 0 to 15 to a hexidecimal character.
4. Repeatedly,
   • take the remainder of the input integer mod 16,
   • convert this remainder to a hexidecimal character,
   • prepend this character to a result string that starts off being empty, and
   • divide the input by 16,
   as long as the input is greater than zero.
5. Prepend the characters 0x to your result String
6. Display your result in the hexidecimal field
7. Handle zero input correctly.
8. Handle negative decimal input correctly.

Lab

• Create a directory inside the Labs directory on your thumbdrive for today's lab.
• Modify the convert.html file from the demonstration to convert from a hexidecimal String back to a decimal integer.
  1. Respond to changes in the hexidecimal field. Create a function convertToDecimal() to handle this.
  2. Complain, if the user enters something that doesn't begin with the String 0x and then return. (Do something similar if ever you detect that the user's input is bogus.)
  3. Create a function that turns a hexidecimal character into an integer from 0 to 15.
  4. Remove the first two characters (0x) from the input.
  5. Creat a variable result and set it to zero.
  6. Repeatedly,
     • multiply result by 16.
     • remove the first input character,
     • convert it to a number,
     • add this number to result,
     as long as the input has more characters.
  7. Convert your result to a String and display it in the decimal field
  8. Handle zero input correctly.
  9. Handle negative decimal input correctly.
• Add links to the files from today's lab to the index.html file in your Labs directory.
• Using FileZilla (or another FTP client), synchronize your website to the image on your thumbdrive.

Always shut down your computer and turn off your display before leaving the lab.