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Detailed explanation of the use of for loop in JavaScript_Basic knowledge

WBOY
WBOYOriginal
2016-05-16 15:56:451452browse

We have seen that there are different variations of while loops. This chapter will introduce another popular loop called the for loop.
for loop

The for loop is the most compact form of a loop and consists of the following three important parts:

  1. Initial value of loop initialization counter. The initialization statement is executed before the loop begins.
  2. Test statement that will test if the given condition is true or false. If the condition is true, then the code given in the loop will be executed, otherwise the loop will exit.
  3. Loop statement that can increase or decrease the counter.

You can separate all three parts on a line with semicolons.
Grammar

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

Example:

The following example illustrates a basic for loop:

<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>

This will produce the following result, which is similar to a while loop:

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! 

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