JavaScript While Loop
Loops execute a block of code
a specified number of times, or while a specified condition is true.
The while Loop
The while loop loops through a block of code while a specified condition is true.
Syntax
while (var<=endvalue)
{
code to be executed
} |
Note: The <= could be any comparing statement.
Example
The example below defines a loop that starts with i=0. The loop
will continue to run as long as i is less than, or equal to 5. i
will increase by 1 each time the loop runs:
Example
<html>
<body>
<script type="text/javascript">
var i=0;
while (i<=5)
{
document.write("The number is " + i);
document.write("<br />");
i++;
}
</script>
</body>
</html> |
Try it yourself »
|
The do...while Loop
The do...while loop is a variant of the while loop. This loop will
execute the block of code ONCE, and then it will
repeat the loop as long as the specified condition is true.
Syntax
do
{
code to be executed
}
while (var<=endvalue); |
Example
The example below uses a do...while loop. The do...while loop will always be
executed at least once, even if the condition is false, because the statements
are executed before the condition is tested:
Example
<html>
<body>
<script type="text/javascript">
var i=0;
do
{
document.write("The number is " + i);
document.write("<br />");
i++;
}
while (i<=5);
</script>
</body>
</html> |
Try it yourself »
|
 |
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