The Boolean object's properties and methods

最新推荐文章于 2020-08-15 01:07:07 发布
原创 最新推荐文章于 2020-08-15 01:07:07 发布 · 771 阅读 · 0 ·
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文章标签：

#properties #methods #object #string #prototype #primitive

博客主要介绍了布尔对象的属性和方法。给出了属性和方法的语法，通过代码示例展示了不同值转换为布尔值的结果，如0、空字符串、null、NaN为false，1和字符串'false'为true，还展示了toString方法的使用。

The Boolean object's properties and methods are described below:

NN: Netscape, IE: Internet Explorer

Properties

Syntax: object.property_name

PropertyDescriptionNNIE 
constructorContains the function that created an object's prototype44
prototypeAllows addition of properties and methods to the object34

Methods

Syntax: object.method_name()

MethodDescriptionNNIE
toString()Converts a Boolean value to a string. This method is called by JavaScript automatically whenever a Boolean object is used in a situation requiring a string44
valueOf()Returns a primitive value ("true" or "false") for the Boolean object44

<script type="text/javascript">
var b1=new Boolean( 0)
var b2=new Boolean(1)
var b3=new Boolean("")
var b4=new Boolean(null)
var b5=new Boolean(NaN)
var b6=new Boolean("false")

document.write("0 is boolean "+ b1 +"<br />")
document.write("1 is boolean "+ b2 +"<br />")
document.write("An empty string is boolean "+ b3 + "<br />")
document.write("null is boolean "+ b4+ "<br />")
document.write("NaN is boolean "+ b5 +"<br />")
document.write("The string 'false' is boolean "+ b6 +"<br />")
document.write("b1.toString()" + b1.toString() +"<br />")
document.write("b2.toString()" + b2.toString() +"<br />")
document.write("b3.toString()" + b3.toString() +"<br />")
document.write("b4.toString()" + b4.toString() +"<br />")
document.write("b5.toString()" + b5.toString() +"<br />")
document.write("b6.toString()" + b6.toString() +"<br />")
</script>

-----------------------------------------------------------------------------------------

0 is boolean false
1 is boolean true
An empty string is boolean false
null is boolean false
NaN is boolean false
The string 'false' is boolean true
b1.toString()false
b2.toString()true
b3.toString()false
b4.toString()false
b5.toString()false
b6.toString()true

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