The for loop is a structure that loops for a preset number of times.
The for loop is made up of two parts: condition and statement.
The condition structure determines how many times the loop repeats.
The statement is what is executed every time the loop occurs.
The condition structure is contained within parentheses and is made up of three parts.
Each part is separated by a semicolon (;).
The first part of the condition structure initializes a variable to a starting value.
In most cases, the variable is declared within this section as well as initialized.
The second part is the conditional statement.
The third and final part determines how the variable should be changed each time the loop is iterated.
The format of the for loop looks like the following:
for (initialize; condition; adjust) { statement; } |
<html>
<SCRIPT LANGUAGE='JavaScript'>
<!--
document.write("<H2>Multiplication table for 4</H2>");
for (var aNum = 0; aNum <= 10; aNum++)
{
document.write("4 X ",aNum," = ",4*aNum,"<BR>");
}
//-->
</SCRIPT>
</html>
or
<html>
<SCRIPT LANGUAGE='JavaScript'>
<!--
document.write("<H2>Multiplication table for 4</H2>");
for (var aNum = 0; aNum <= 10;)
{
document.write("4 X ",aNum," = ",4*aNum,"<BR>");
aNum++
}
//-->
</SCRIPT>
</html>
Another for loop example
<HTML>
<HEAD>
<TITLE>
Using the JavaScript for Loop
</TITLE>
</HEAD>
<BODY>
<H1>Using the JavaScript for Loop</H1>
<SCRIPT LANGUAGE="JavaScript">
<!--
var i, total
total = 0
for (i = 1; i < 5; i++) {
total += i
document.write("Loop iteration " + i + " (Cumulative total = " + total + ")<BR>")
}
// -->
</SCRIPT>
</BODY>
</HTML>
Reversed for loop example
<html>
<head>
<title>A Simple Page</title>
<script language="JavaScript">
<!--
for (x = 10; x >= 0; x = x - 2)
{
document.write(x+" " );
}
// -->
</script>
</head>
<body>
</body>
</html>
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