HTML and CSS Reference
3. Locate the input element for the Clear button and add an onclick attribute to run
the clearWin() function when the button is clicked.
4. Locate the input element for the backspace button ( <- ) and add an onclick attri-
bute to run the erase() function when the button is clicked.
5. Add an onclick attribute to the equal button (=) to run the calcExpression()
function when the button is clicked.
6. Scroll to the top of the file and add the calcPress() function to the embedded
script element. The purpose of this function is to append a symbol to the text
displayed in the calculator screen. The calcPress() function should include the
a. A single parameter named symbol
b. A command that uses the += operator to add the value of the symbol parameter to
the value of the calcwindow field within the calculator form
7. Create a function named calcExpression() . The purpose of this function is to
append the calculated value to the expression displayed on the calculator screen.
The function has no parameters. Add the following commands:
a. Declare a variable named cString that is equal to the text contained in the
calcwindow field of the calculator form.
b. Use the eval() method to store the numeric value of cString in a variable named
c. Change the text string value of the calcwindow field from the calculator form to
cString = cValue
where cString is the value of the cString variable and cValue is the value of the
8. Create a function named clearWin() . The purpose of this function is to erase the
contents of the calculator screen. The function has no parameters but should have a
single command that changes the value of the calcwindow field in the calculator to
an empty text string (“”).
9. Save your changes to the file.
10. Open the calculator.htm file in your Web browser. Click the different calculator
buttons and verify that you can enter a mathematical expression into the calculator.
Click the backspace button ( <- ) and verify that you can erase the last character from
the screen. Click the equal button (=) and verify that the calculator adds the calcu-
lated numeric value to the expression. Finally, click the Clear button and verify that
all of the text is removed from the calculator screen.
11. Submit your completed project to your instructor, in either printed or electronic
form, as requested.
Case Problem 3
Write a script
to create a
data Files needed for this case Problem: guesstxt.htm, headmenu.jpg, kglog.jpg,
kgstyles.css, links.jpg, modernizr-1.5.js, title.jpg
Kiddergarden Pete Burnham manages the Web site Kiddergarden, a family-friendly site
containing games, puzzles, stories, and other activities. Pete has asked for your help in
developing a Web page containing a number guessing game.
Pete needs you to create a script that generates a random integer between 1 and 500.
A user has up to 10 guesses to guess the number. After each guess, the page will tell the
user whether his or her guess is too high, too low, or exactly correct. A preview of the
page is shown in Figure 11-40.