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JavaScript 3 (Readings: Ch. 15 Knuckles)
COMM 1213 H1 COMP 4923 X1 JavaScript 3 (Readings: Ch. 15 Knuckles)
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Outline FOR Loop WHILE Loop Verifying Input using a Loop
Sodexo Survey revisited
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Repetition via Loops (Ch.15)
Sets initial loop index value The FOR Loop <HTML> <HEAD> <SCRIPT LANGUAGE=JavaScript><!-- for (i=1; i<=1000 ; i=i+1) { document.write(i+"<BR>"); } //--></SCRIPT> </HEAD> <BODY> <P> </BODY> </HTML> Sets Boolean condition on which to stop Sets amount to change index on each pass of loop What would happen if the condition i<=1000 was changed to i<= ?
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Using For Loops Processing the Pizza Toppings Form
Figure 15.4 Generating random lottery numbers Figure 15.6
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The WHILE Loop Used when the number of times to loop is not known at the time of writing the code. Consider the question: Starting from 1, how many numbers must be added until the total exceeds 25,000. Algorithm: sum = 0 i=1 while sum <= 25000 sum = sum + i i= i+1 Program – Figure 15.8
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Verifying Input Figure 15.10 <HTML> <HEAD>
<SCRIPT LANGUAGE=JavaScript><!-- var pass; pass=prompt("Enter Your Password.",""); correct=false; while(!correct){ if((pass!="buddy")&&(pass!="pal")){ alert("You have entered an incorrect password."); pass=prompt("Enter Your Password. Get it right this time.",""); } else{ correct=true; //--></SCRIPT> </HEAD> <BODY BGCOLOR="#FFFFCC"> <P><FONT SIZE="+3"><B>This page contains the darkest secrets of the universe.</B></FONT> </BODY> </HTML> Figure 15.10
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Other Fun with LOOPs Nested Loops and Tables Figure 15.12
The Sodexo Food survey revisisted The Sodexo Food survey with a Loop Uses an array to hold the Food types The Sodexo Food survey with HTML output
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Resources http://www.w3schools.com/js/js_examples.asp
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THE END danny.silver@acadiau.ca
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