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LetterGrades

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In this project, you will create and?x a document with a simple form;that displays the value of a letter grade.;1. Create a new document in your text editor.;2. Type the declaration, element, document;head, and element. Use the Transitional DTD and;?Letter Grades? as the content of the element.;3. Create a script section in the document head that includes the;following checkGrade() function and switch statement;4. Add the following form to the document body that includes;an onclick event handler that calls the checkGrade();function. The value of the single text box is passed to the;checkGrade() function.;5. Save the document as LetterGrades.html in the Exercises;folder for Chapter 8, and then open it in your Web browser.;You should receive an error message about a missing brace.;The problem is that the statements within the switch state-;ment are not contained within braces. Modify the switch;statement so that it includes braces, as follows;switch (grade);case "A;window.alert("Your grade is excellent.;break;case "B;window.alert("Your grade is good.;break;case "C;window.alert("Your grade is fair.;break;case "D;window.alert("You are barely passing.;break;case "F;window.alert("You failed.;break;default;window.alert("Invalid letter!;6. Save the LetterGrades.html document, and reload it in;your Web browser window. You should receive another error;message about a missing closing parenthesis. Each of the;window.alert() statements in the switch statement is miss-;ing a closing parenthesis. Add the closing parenthesis to each;of the window.alert() statements, between the closing quo-;tation mark and the semicolon.;7. Save the LetterGrades.html document, and reload it in your;Web browser window. You should not receive any more error;messages when you reload the page. However, if enter a grade;into the text box and click the Check Grade button, you will see;an additional error about ?grade? not being de?ned. The prob-;lem that causes this error is that the checkGrade() function def-;inition does not include the grade parameter, which is used in;the switch statement to evaluate the letter grade. Add the grade;parameter to the checkGrade() function de?nition, as follows;function checkGrade(grade) {...;8. Save the LetterGrades.html document, and reload it in your;Web browser window. Try entering a valid grade into the text;box and clicking the Check Grade button. No matter what;value you enter, you will always see the message ?Invalid let-;ter!? in the alert box. The problem that is causing this error;is that the button element, which calls the checkGrade();function, is incorrectly passing a value to the function of;this.value. The value of the grade text box, not the value;of the button, must be passed to the checkGrade() function.;Modify the argument that is passed to the checkGrade();function, as follows;onclick="checkGrade(document.forms[0].grade.value),;9. Save the LetterGrades.html document, and then validate the;document with the W3C Markup Validation Service. Once;the document is valid, close it in your text editor and reload it;in your Web browser window. The script should now function;correctly.;10. Close your Web

 

Paper#69495 | Written in 18-Jul-2015

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