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





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")