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What are Logical Operators in JavaScript?


JavaScript supports the following logical operators. Assume variable A holds 10 and variable B holds 20, then,

Sr.No
Operator and Description
1
&& (Logical AND)
If both the operands are non-zero, then the condition becomes true.
Ex: (A && B) is true.
2
|| (Logical OR)
If any of the two operands are non-zero, then the condition becomes true.
Ex: (A || B) is true.
3
! (Logical NOT)
Reverses the logical state of its operand. If a condition is true, then the Logical NOT operator will make it false.
Ex: ! (A && B) is false.


Example

You can try the following code to learn how to implement Logical Operators in JavaScript −

Live Demo

<html>
   <body>
      <script>
         <!--
            var a = true;
            var b = false;
            var linebreak = "<br />";
            document.write("(a &amp;&amp; b) => ");
            result = (a &amp;&amp; b);
            document.write(result);
            document.write(linebreak);
            document.write("(a || b) => ");
            result = (a || b);
            document.write(result);
            document.write(linebreak);
            document.write("!(a &amp;&amp; b) => ");
            result = (!(a &amp;&amp; b));
            document.write(result);
            document.write(linebreak);
         //-->
      </script>
      <p>Set the variables to different values and different operators and then try...</p>
</body>
</html>