CS 101   Web Construction,  Summer 2006,  Instructor:  Jeffrey Horn

• Assignment 5  "Much Tougher Captcha!"

  • Handed out:  Tuesday, Oct. 23, 2007
  • Due:  
  • Purpose:
    1. More Javascript programming (random numbers -> random behavior)
    2. Learn to use html forms for user interaction
    3. More complex use of the conditional statement ("if-then-else")
  • Background:
    • Wikipedia entry for Captcha
    • Sample Code from class
  • Details:
    • Build on your Assignment 4 web page.
    • Make your Assignment 4 web page even harder for a non-human viewer to get through.  In Assignment 4, there was a single Captcha image for the user to read and get the characters from.  This means that the next time the page is visited, the hidden string will be the same and someone could write a program that submits the same string everytime.
    • So for this assignment, get multiple Captcha images, say five (5), and make them all different.
    • Then use a random number to choose which image to show the user when the page is viewed. 
    • If the user submits the matching character string, then let them through,
    • otherwise, let them try again, BUT WITH A NEW CAPTCHA IMAGE randomly chosen from the five!
  • Grading:  Total 100 pt.s.   The usual grading scale (i.e., 90 to 100 pt.s is an A, 80 to 89 pt.s is a B, etc.)
  • Turn-in Procedure:  Put your web pages on the web (use your myweb.nmu.edu web site or your own web server account if you have one).  Email me the URL for this assignment:  (jhorn@nmu.edu).  Keep it "secret"!  Use an obscure URL.