2. 1 CS1301 Introduction To Computer Programming (07-08 Semester B) www.cs.cityu.edu.hk/~helena Lecture Exercise (Wk8) Q.1 [Use of while-loop] (a) Write a function that returns a string which contains all 3’s multiples from 0 to 30 (each number should be followed by a line break): … function listNumbers() { } … (b) Modify the above function such that each number is indicated with an “(odd)” or “(even)” label:

3. 2 CS1301 Introduction To Computer Programming (07-08 Semester B) www.cs.cityu.edu.hk/~helena Lecture Exercise (Wk8) Q.2 Write the code that asks the user to input 2 temperatures in Fahrenheit, say 95 and 105 (using the prompt dialog). Then display the table of temperature conversions within the range (using document.write). Temperature Conversions Temperature Conversion (Fahrenheit to Celsius)

4. 3 CS1301 Introduction To Computer Programming (07-08 Semester B) www.cs.cityu.edu.hk/~helena Lecture Exercise (Wk8) Q.3 ROUND THE CLOCK The following shows a clock value (24 hours: 0,1,2,..23,0,1,2..). When the user clicks "Advance 1 hour", the clock is updated. Rewrite the code by using % CS1301 DEMO var c=0; //Global variable: the clock value //advance the clock function move() { c=c+1; if (c==24) c=0; document.getElementById('time').innerHTML=c; } 0 O'clock Advance 1 hour

5. 4 CS1301 Introduction To Computer Programming (07-08 Semester B) www.cs.cityu.edu.hk/~helena Lecture Exercise (Wk8) Q.4 The Photo Gallery application : Change the code to add the "Change Page Size" button (number of images per page) and make it work: //Current left most image number in the page var currentStartImageNum=1; //Update the page: paragraph of images function makeHtmlOfImages() {var i; var htmlOfImages=''; i=currentStartImageNum; while (i<=currentStartImageNum+3) { htmlOfImages = htmlOfImages + ' '; i++; } document.getElementById('images').innerHTML=htmlOfImages; } //Show next page function goNext() { if (currentStartImageNum==17) { alert('This is the last page'); return; } currentStartImageNum=currentStartImageNum+4; makeHtmlOfImages(); } //Show previous page function goPrev() { if (currentStartImageNum==1) { alert('This is the first page'); return; } currentStartImageNum=currentStartImageNum-4; makeHtmlOfImages(); } … … - Classify the variables used above. Global variables: Local variables: - Can we change all the global variables to local? - Should we change all the local variables to global?