PGDEL/DECP03/Unit3/19

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DECP 03

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Unit 3.3 Web application development tools & Technologies Conditional statement

Conditional Statement	Syntax	Example
If statement: The condition checking statement in JavaScript is if-else construct, used to construct the flow of program.	if(condition){ //JavaScipt statements }	var book =”JavaScript” if ( book = = ”JavaScript”) { document.writeln(“ JavaScript book.”); }
Conditional Statement: If evaluates either true or false depending on the evaluation of the condition. If the condition evaluated to true then the result will be Value 1 otherwise Value2	(Condition) ? Value 1 : Value 2	var book =”JavaScript” ( book = = ”JavaScript”) ? “JavaScript book.” : “Other Book”

Loop Statement

Loop is the ability to repeat some block of code, for the purpose JavaScript has two types of loop statements:

Loop	Syntax	Example
For loop This is used to repeat certain block of code (statements) in specified number of times.	for (expression 1; expression 2; expression 3){ // JavaScript statements } Expression 1 sets up the counter variable. Expression 2 is the condition, the loop will execute till condition evaluates to true. Expression 3 is to update the counter variable specified in expression 1.	for( var count =1; count<=10; count++){ document.writeln(count); } The following code prints numbers from 1 to 10.
While loop This is used to repeat certain block of code (statements), which until a condition met.	while(expression){ // JavaScript statements } Expression is a condition that evaluates to a Boolean value .The statements will execute as long as the condition is true.	var count =1; while(count<=10){ document.writeln(count); count++; } The following code prints numbers from 1 to 10.

Work in progress, expect frequent changes. Help and feedback is welcome. See discussion page.