Page 333 - Web Applications (803) Class 11
P. 333
The do….while Loop
Do while is a different type of loop than either the for or while loops. This loop will always execute the statement at
least once, even if the condition is false. After one iteration of the loop has been completed, the condition is checked.
Depending on the condition, the loop will continue to run further or terminate.
Syntax of the do…while loops is as follows:
initialisation_expression;
do
{
//Loop body
update_expression;
} while (conditional_expression);
Where,
Ðinitialisation_expression: In this expression, a variable is initialized outside the loop.
Ð
Ð Ðupdate_expression: The loop control variable is updated here.
Ð Ðconditional_expression: Similar to for loop, this expression contains a logical condition which evaluates either true
or false.
Flow Diagram
do...while Loop Body
True Test
Condi
on
False
Loop Terminates
Example:
<HTML>
<BODY text="blue">
<H2> Using do...while loop </H2>
<script>
var i = 2;
document.write("Loop to display even numbers less than 20 <br><br>");
do
{
document.write(i + "<br><br>");
i = i + 2;
}while(i<20);
</SCRIPT>
</BODY>
</HTML>
Introduction to Dynamic Websites Using JavaScript 331

