|| (Logical OR) : Boolean Operators « Operators « JavaScript Tutorial

Home
JavaScript Tutorial
1.Language Basics
2.Operators
3.Statement
4.Development
5.Number Data Type
6.String
7.Function
8.Global
9.Math
10.Form
11.Array
12.Date
13.Dialogs
14.Document
15.Event
16.Location
17.Navigator
18.Screen
19.Window
20.History
21.HTML Tags
22.Style
23.DOM Node
24.Drag Drop
25.Object Oriented
26.Regular Expressions
27.XML
28.GUI Components
29.Dojo toolkit
30.jQuery
31.Animation
32.MS JScript
JavaScript Tutorial » Operators » Boolean Operators 
2.6.5.|| (Logical OR)

The logical OR operator in JavaScript is the same as in Java, using the double pipe (||):

var bTrue = true;
var bFalse = false;
var bResult = bTrue || bFalse;

Logical OR behaves as described in the following truth table:

Operand 1Operand 2Result
truetruetrue
truefalsetrue
falsetruetrue
falsefalsefalse


Just like logical AND, if either operand is not a Boolean, logical OR will not always return a Boolean value:

If one operand is an object and one is a Boolean, the object is returned.

If both operands are objects, the first operand is returned.

If both operands are null, null is returned.

If either operand is NaN, NaN is returned.

If either operand is undefined, an error occurs.

<html>
    <script language="JavaScript">
    <!--
    x = 8;
    if((8==x|| (x=7))
    {
      document.write("The || evaluated TRUE!<br>");
    }
    else
    {
      document.write("The || evaluated FALSE!<br>");
    }
    document.write("x=",x,"<br>");
    -->
    </script>
    </html>
2.6.Boolean Operators
2.6.1.JavaScript provides three Boolean operators
2.6.2.Logical AND
2.6.3.! (Logical NOT)
2.6.4.Use logical NOT to control the loop
2.6.5.|| (Logical OR)
java2s.com  | Contact Us | Privacy Policy
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.