JavaScript by Example: JavaScript Core Objects. Pt. 2

<html>

<head><title>Number Object</title>

</head>

<h2>

Formatting Numbers

</h2>

1 var n = new Number(22.425456);

2 document.write("<b>The unformatted number is " + n + "<br>");

3 document.write("The formatted number is "+ n.toFixed(2) +

"<br>");

4 document.write("The formatted number is "+ n.toFixed(3) +

"<br>");

</script>

</body>

</html>

A new Number object is created and assigned to the variable n.

The value of the number is displayed as a large floating-point number, 22.425456.
The Number object's toFixed() method gets an argument of 2. This fixes the decimal point two places to the right of the decimal point and rounds up if necessary. The new value is 22.43.
This time the toFixed() method will format the number with three numbers to the right of the decimal point. (See Figure 9.30.)


var object = new Boolean(value); Example: var b1 = new Boolean(5); var b2 = new Boolean(null);

var object = new Boolean(value);

Example:

var b1 = new Boolean(5);

var b2 = new Boolean(null);


<html><head><title>Boolean Object</title> </head> <body bgcolor=aqua> <font face="arial" size="+1"><b> The Boolean Object<br> <font size="-1"> <script language="JavaScript"> 1 var bool1= new Boolean( 0); var bool2 = new Boolean(1); var bool3 = new Boolean(""); var bool4 = new Boolean(null); var bool5 = new Boolean(NaN); 2 document.write("The value 0 is boolean "+ bool1 +"<br>"); document.write("The value 1 is boolean "+ bool2 +"<br>"); document.write("The value of the empty string is boolean "+ bool3+ "<br>"); document.write("The value of null is boolean "+ bool4+ "<br>"); document.write("The value of NaN is boolean "+ bool5 +"<br>"); </script> </body></html>

<html><head><title>Boolean Object</title>

</head>

The Boolean Object<br>

1 var bool1= new Boolean( 0);

var bool2 = new Boolean(1);

var bool3 = new Boolean("");

var bool4 = new Boolean(null);

var bool5 = new Boolean(NaN);

2 document.write("The value 0 is boolean "+ bool1 +"<br>");

document.write("The value 1 is boolean "+ bool2 +"<br>");

document.write("The value of the empty string is boolean "+

bool3+ "<br>");

document.write("The value of null is boolean "+ bool4+ "<br>");

document.write("The value of NaN is boolean "+ bool5 +"<br>");

</script>

</body></html>


The argument passed to the Boolean object constructor is the initial value of the object, either true or false. If the initial value is 0, the empty string "", NaN, or null, the result is false; otherwise, the result is true.
The Boolean object's values are displayed as either true or false. (See Figure 9.31.)

The argument passed to the Boolean object constructor is the initial value of the object, either true or false. If the initial value is 0, the empty string "", NaN, or null, the result is false; otherwise, the result is true.

The Boolean object's values are displayed as either true or false. (See Figure 9.31.)

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