Subtract

The subtract operator is -.

 
<!DOCTYPE html>
<html>
<head>
    <title>Example</title>
    <script type="text/javascript">
    
        var result = 2 - 1; 
        document.writeln(result); //1
               
    </script>
</head>
<body>
</body>
</html>

Click to view the demo

Rules for subtract operator(Operand 1 - Operand 2 = Result):

Operand 1	Operand 2	Result
number	number	arithmetic subtract
NaN	a number	NaN
a number	NaN	NaN
Infinity	Infinity	NaN
-Infinity	-Infinity	NaN
Infinity	-Infinity	Infinity
-Infinity	Infinity	-Infinity
+0	+0	+0
+0	-0	-0
-0	-0	+0

If either operand is a string, a Boolean, null, or undefined, it is converted to a number using Number(). If either operand is an object, its valueOf() method is called to retrieve a numeric value. If the object doesn't have valueOf() defined, then toString() is called and the resulting string is converted into a number.

 
<!DOCTYPE html>
<html>
<head>
    <title>Example</title>
    <script type="text/javascript">
        document.writeln(2 - true); //1, true is converted to 1 
        document.writeln(NaN - 1);  //NaN 
        document.writeln(2 - 3);    // -1
        document.writeln(2 - "");  //2 , "" is converted to 0 
        document.writeln(2 - "2"); //0, "2" is converted to 2 
        document.writeln(2 - null); //2, null is converted to 0     </script>
</head>
<body>
</body>
</html>

Click to view the demo