Casting to Number : Type Conversion « Number Data Type « JavaScript Tutorial

Home
JavaScript Tutorial
1.Language Basics
2.Operators
3.Statement
4.Development
5.Number Data Type
6.String
7.Function
8.Global
9.Math
10.Form
11.Array
12.Date
13.Dialogs
14.Document
15.Event
16.Location
17.Navigator
18.Screen
19.Window
20.History
21.HTML Tags
22.Style
23.DOM Node
24.Drag Drop
25.Object Oriented
26.Regular Expressions
27.XML
28.GUI Components
29.Dojo toolkit
30.jQuery
31.Animation
32.MS JScript
JavaScript Tutorial » Number Data Type » Type Conversion 
5.8.12.Casting to Number

The Number() type cast works in a manner similar to parseInt() and parseFloat().

Except that it converts the entire value, not just part of it.

parseInt() and parseFloat() only convert up to the first invalid character (in strings),so "4.5.6" becomes "4.5".

Using the Number() type cast, "4.5.6".

If a string value can be converted entirely, Number() decides whether to use parseInt() or parseFloat().

UsageResult
Number(false)0
Number(true)1
Number(undefined)NaN
Number(null)0
Number("5.5")5.5
Number("56")56
Number("5.6.7")NaN
Number(new Object())NaN
Number(100)100


5.8.Type Conversion
5.8.1.Type Conversion
5.8.2.Type-conversion adheres to the following rules
5.8.3.Converting to a String
5.8.4.Using Number's toString() method in radix mode
5.8.5.Converting to a Number
5.8.6.parseInt() method
5.8.7.parseInt() in radix mode
5.8.8.If decimal numbers contain a leading zero, it's always best to specify the radix as 10 so that you won't accidentally end up with an octal value.
5.8.9.parseFloat() method
5.8.10.Type Casting
5.8.11.Casting to Boolean value
5.8.12.Casting to Number
5.8.13.Casting type to string
5.8.14.parseInt("33.00")
5.8.15.parseFloat("1.23e-2")
5.8.16.parseFloat("1.45inch")
java2s.com  | Contact Us | Privacy Policy
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.