"for" Loop Statement Example

This section provides a JavaScript tutorial example showing how to write a 'for' loop statement.

To help you understand how "for" loop statements work, I wrote the following the JavaScript tutorial example, For_Loop_Statements.html:

```<html>
<!-- For_Loop_Statements.html
-->
<body>
<pre>
<script type="text/javascript">
var i, j, is_prime;
for ( i=3; i<=30; i+=2 ) {
is_prime = true;
for ( j=2; j<=i/2; j++) {
is_prime = i%j > 0;
if (!is_prime) break;
}
if (is_prime)
document.write("Found a prime number: " + i + ".\n");
}
</script>
</pre>
</body>
</html>
```

Note that:

• This JavaScript uses a nested "for" loop statements to calculate prime numbers.
• The outer "for" loop uses variable "i" to control the loop execution.
• The inner "for" loop uses variable "j" to control the loop execution.
• The outer "for" loop's stop condition is "i<=30". The value of "i" is increased by 2 in each iteration.
• The inner "for" loop's stop condition is "j<=i/2". The value of "j" is increased by 1 in each iteration.
• The inner "for" loop has a "break" statement that will break the loop when "is_prime" is true.

The output of this sample JavaScript is:

```Found a prime number: 3.
Found a prime number: 5.
Found a prime number: 7.
Found a prime number: 11.
Found a prime number: 13.
Found a prime number: 17.
Found a prime number: 19.
Found a prime number: 23.
Found a prime number: 29.
```