Pre-Increment : Prefix operator « Operators « JavaScript Tutorial






  1. JavaScript Tutorial
  2. Operators
  3. Prefix operator

The pre-increment operator is placed directly before the variable.

The operation begins by incrementing the variable by 1.

The new incremented value is returned by the operation to be used in another expression.

If the variable is a string, it is converted to a number.

For example, the following segment of code

var price = 5
var newPrice = (++price) + 3;

the value of 9 dollars would be stored in the variable newPrice.

<html>
    <script language="JavaScript">
    <!--
    document.write("<h3>Before Pre-decrement</h3>");
    num = new String("8");
    document.write("num=",num,"<br>"); 
    returnValue = --num;
    document.write("<h3>After Pre-decrement</h3>");
    document.write("num=",num,"<br>");
    document.write("Value returned from operation is ",returnValue,"<br>");
    returnValue = num--;
    document.write("<h3>After Post-decrement</h3>");
    document.write("num=",num,"<br>");
    document.write("Value returned from operation is ",returnValue,"<br>");
    -->
    </script>
    </html>








2.3.Prefix operator
2.3.1.Pre-Increment
2.3.2.Pre-Decrement
2.3.3.Prefix operator: ++
2.3.4.Prefix operator 2: --