Page 299 - Web Applications (803) Class 11
P. 299
Logical Operators
The logic between variables or values is determined using logical operators. The table below explains the logical
operators given a = 6 and b = 3:
Operator Name Description Example Output
&& AND It returns true if and only if both the operands return (a < 10 && b > 1) True
true, and false if even one of the operands returns false.
|| OR It returns false if and only if both the operands return (a == 5 || b == 5) False
false, and it returns true if any one of the operands
returns true.
! NOT It is used to invert the value of a boolean condition, !(a == b) True
which means reversing the logical (true or false) state of
the value.
Example:
<!DOCTYPE HTML>
<HTML>
<HEAD>
<TITLE> logical Operators </TITLE>
</HEAD>
<BODY>
<SCRIPT>
var x = 5;
var y = 6;
result = (x<y && x>!y);
document.write( "And operator result is"+"="+result);
document.write("<br>");
result = (x<y || x>y);
document.write("OR operator result is"+"="+result);
document.write("<br>");
result = (!(x && y));
document.write( " NOT operator result is"+"="+result);
</SCRIPT>
</BODY>
</HTML>
Output of the above code is as follows:
Introduction to Dynamic Websites Using JavaScript 297

