HTML and CSS Reference
In-Depth Information
Using Number Constants and Different Bases. The constants MAX_VALUE ,
MIN_VALUE , NEGATIVE_INFINITY , POSITIVE_INFINITY , and NaN are properties of
the Number() function, but are not used with instances of the Number object; thus, var
huge = Number.MAX_VALUE is valid, but huge.MAX_VALUE is not. NaN is a special
value that is returned when some mathematical operation results in a value that is not
a number.
The methods provided to the Number object manipulate instances of number objects.
For example, to convert numbers to strings representing different bases, the toString()
method manipulates a number, either primitive or object. See Example 9.31.
EXAMPLE 9.31
<html>
<body bgcolor="orange"><font color="black" size="+1">
<h2>Constants</h2>
<script type="text/javascript">
1
var largest = Number.MAX_VALUE;
2
var smallest = Number.MIN_VALUE;
3
var num1 = 20; // A primitive numeric value
4
var num2 = new Number(13); // Creating a Number object
document.write("<b>The largest number is " + largest
+ "<br />");
document.write("The smallest number is "+ smallest
+ "<br />");
5
document.write("The number as a string (base 2): "+
num1.toString(2) );
6
document.write("<br />The number as a string (base 8): "+
num2.toString(8) );
7
document.write("<br />The square root of -25 is: "+
Math.sqrt(-25) + "<br />");
</script>
</body>
</html>
EXPLANATION
1
The constant MAX_VALUE is a property of the Number() function. This constant
cannot be used with an instance of a Number object.
2
The constant MIN_VALUE is a property of the Number() function.
3
A number is assigned to the variable called num1 .
4
A new Number object is created with the Number() constructor and assigned to
num2 . It is easier to use the literal notation: num2 = 13 .
5
The number is converted to a string represented in binary, base 2.
6
The number is converted to a string represented in octal, base 8.
7
The square root of a negative number is illegal. JavaScript returns NaN , not a
number, when this calculation is attempted (see Figure 9.36).

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