The while Loop
By Stephen Bucaro
A loop structure allows you execute a series of statements over and over. Several
kinds of loop structures are available in Java Script, the while loop evaluates
an expression, and while the expression evaluates to true, the while
loop will repeatedly execute the series of statements. The syntax for the while
loop is shown below.
An example of a while loop is shown below.
var price = 10.00;
while(price > 5.00)
price -= 1.00;
alert("The final price is: " + price);
The Condition expression inside the brackets is evaluated. The result
of that evaluation can be true or false. If the result is true
the statements inside the curly brackets will be executed. If the result is
false, the loop terminates and program flow continues with the next
statement following the while loop structure.
In the example above, the variable price is initialized to 10.00. The
Condition expression inside the while brackets tests the value of price
to see if it's greater than 5.00. If the value of price is greater than 5.00,
the statements inside the curly brackets are executed; 1.00 is subtracted from
price. The condition expression again tests the value of price.
After the statements inside the curly brackets are executed five times, the
value of price is no longer greater than 5.00. The result of the condition
expression evaluation becomes false, the while loop terminates.
program flow continues with the next statement following the while loop
structure, which creates a message box displaying the final value of price (5.00).
More Java Script Code:
• Java Script alert Message Box
• Generating Random Numbers
• The Conditional Operator
• Java Script prompt Message Box
• The while Loop
• Comparison Operators
• Extract Part of a String
• The Document Object Model (DOM)
• Convert a Number to a String