LIS 7008 - Information Technologies and Systems
Spring 2017 - Section 01
Assignment 6

Explanation

The JavaScript program that we looked at in the lecture notes (i.e., selector.html) is a good start, but a real search tool selector would probably need to provide more options and do more sophisticated selection. It is therefore important that you learn how to modify JavaScript that you find on the Web to suit your purposes. In this assignment, you will modify selector.html in two ways, and post your modified page on your Web site for the instructor to grade.

If you have not downloaded the page, please do so here: shorthand version or full version (with semicolons and complete braces)

What the program does

Your Task: Modify the Program

Task 1. The library board has decided that people aged 16 and over should be treated as adults by the search tool selector. Change your copy of the page to implement this new policy.

Task 2. Your library director has learned that a recent report published in the Journal of Internet Stuff has revealed that people over 40 prefer the Yahoo! search engine (http://www.yahoo.com), but that adults aged 40 and under prefer Google (www.google.com). Change your copy of the page to send adults to the search engine that they are most likely to like based on their age (if they select a search engine).

Save your work as hw6.html (or whatever filename you like), then link this from your 7008.html Web page you created for HW4.

Testing

Here are the age specifications and expected results:

• Age 0 to 15 - Kidrex.org, kids.usa.gov
• Age 16 to 40 - Google and dmoz.org
• Age 41 to 119 - Yahoo! and dmoz.org
• Age 120 and above - Invalid

Common problems and solutions:

• Before revising the program, try to understand the logic of the program first (e.g., those functions, if-else statements, and how those functions interact with each other). Do not try to revise anything before you understand the whole program. (Similarly do not jump into the water if you do not know how deep/cold the water is.) When adding/revising functions, make your logic clear. When making if-else statements, make mutually exclusive statements. For example, in the statement if Condition A go east else go west, "Condition A and else (not-A)" are mutually exclusive conditions. If you use "if - else if - else" statements, please make those conditions mutually exclusive.

• You cannot use statements like "(age>40)" or "(age > 15 && age < 40)" in the "function adult_jump()" because that function does not have an "age" parameter and does not define an "age" variable; try to use other functions [such as is_adult(age) or is_kid(age)] to replace those statements. Hint: you may want to revise those smaller functions and/or write new ones to meet your needs.

• "Your specified website directs me to a different website."
  You do not have to worry about it. This is a programming exercise. I use the website as an example only. I do not care where it finally directs you as long as it is a serious website.

• "I do not know what is wrong with my program; it simply does not work."
  The syntax of the programming language is very rigorous, so please pay great attention to the things you add, revise, or delete. It is very common that right after changing anything in the program, it does not work. In this case, please check whether you have lost any parentheses "()" and braces "{}"; check typos (such as functoin, retrun) and inconsistent function names.

  Also, Internet Explorer has a Javascript debugger. Here is a tutorial on HOW-TO: Debug JavaScript in Internet Explorer . Reminder: the debugger checks your syntax only; it does not check your semantics (logic). If you know what it does and how it works, it can be helpful to you, otherwise it can be useless because it produces error messages you do not understand. Therefore, please do not depend on it totally.

  If you have other questions, please ask me or TA. Please do not feel frustrated if you cannot make it work finally. I have the special grading policy addressed above to protect you.

Grading rubric:

These are the most common categories. You can actually grade your work by yourself.