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JavaScript - For Loop

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The 'for' loop is the most compact form of looping. It includes the following three important parts −

  • The loop initialization where we initialize our counter to a starting value. The initialization statement is executed before the loop begins.

  • The test statement which will test if a given condition is true or not. If the condition is true, then the code given inside the loop will be executed, otherwise the control will come out of the loop.

  • The iteration statement where you can increase or decrease your counter.

You can put all the three parts in a single line separated by semicolons.

Flow Chart

The flow chart of a for loop in JavaScript would be as follows −

For Loop

Syntax

The syntax of for loop is JavaScript is as follows −

for (initialization; test condition; iteration statement) {
   Statement(s) to be executed if test condition is true
}

Example

Try the following example to learn how a for loop works in JavaScript.

Live Demo 
<html>
   <body>      
      <script type = "text/javascript">
         <!--
            var count;
            document.write("Starting Loop" + "<br />");
         
            for(count = 0; count < 10; count++) {
               document.write("Current Count : " + count );
               document.write("<br />");
            }         
            document.write("Loop stopped!");
         //-->
      </script>      
      <p>Set the variable to different value and then try...</p>
   </body>
</html>

Output

Starting Loop
Current Count : 0
Current Count : 1
Current Count : 2
Current Count : 3
Current Count : 4
Current Count : 5
Current Count : 6
Current Count : 7
Current Count : 8
Current Count : 9
Loop stopped! 
Set the variable to different value and then try...
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