JScript provides many data types to use in your programs. These types can be divided into two main categories, value data types and reference data types (also referred to as JScript objects). To add types to JScript, you can import namespaces or packages that contain new data types, or you can define new classes that can be used as new data types.

Data Type Details

The following table shows the value data types supported by JScript. The second column describes the equivalent Microsoft .NET Framework data type. You can declare a variable of the .NET Framework type or the JScript value type and achieve exactly the same results. The storage size (where applicable) and range are also given for each type. The third column lists the amount of storage required for one instance of a given type, if applicable. The fourth column provides the range of values that can be stored by a given type.

JScript value type	.NET Framework type	Storage size	Range
boolean	Boolean	N/A	true or false
char	Char	2 bytes	Any Unicode character
float (single-precision floating-point)	Single	4 bytes	Approximate range is -1038 to 1038 with accuracy of about 7 digits. Can represent numbers as small as 10-44.
Number, double (double-precision floating-point)	Double	8 bytes	Approximate range is -10308 to 10308 with accuracy of about 15 digits. Can represent numbers as small as 10-323.
decimal	Decimal	12 bytes (integral part)	Approximate range is -1028 to 1028 with accuracy of 28 digits. Can represent numbers as small as 10-28.
byte (unsigned)	Byte	1 byte	0 to 255
ushort (unsigned short integer)	UInt16	2 bytes	0 to 65,535
uint (unsigned integer)	UInt32	4 bytes	0 to 4,294,967,295
ulong (unsigned extended integer)	UInt64	8 bytes	0 to approximately 1020
sbyte (signed)	SByte	1 byte	-128 to 127
short (signed short integer)	Int16	2 bytes	-32,768 to 32,767
int (signed integer)	Int32	4 bytes	-2,147,483,648 to 2,147,483,647
long (signed extended integer)	Int64	8 bytes	Approximately -1019 to 1019
void	N/A	N/A	Used as the return type for a function that does not return a value.

The next table shows the reference data types (JScript objects) that JScript provides and that can be used as types. Reference types do not have a predefined specific storage size.

JScript reference type	.NET Framework type	Refers to
ActiveXObject	No direct equivalent	An Automation object.
Array	Interoperates with Array and typed arrays	Arrays of any type.
Boolean	Interoperates with Boolean	A Boolean value, either true or false.
Date	Interoperates with DateTime	Dates are implemented using the JScript Date object. The range is approximately 285,616 years on either side of January 1, 1970.
Enumerator	No direct equivalent	An enumeration of items in a collection. For backward compatibility only.
Error	No direct equivalent	An Error object.
Function	No direct equivalent	A Function object.
Number	Interoperates with Double	A numeric value with an approximate range of -10308 to 10308 and with an accuracy of about 15 digits. Can represent numbers as small as 10-323.
Object	Interoperates with Object	An Object reference.
RegExp	Interoperates with Regex	A regular expression object.
String Data Type (variable-length)	String	0 to approximately 2 billion Unicode characters. Each character is 16 bits (two bytes).
String Object (variable-length)	Interoperates with String	0 to approximately 2 billion Unicode characters. Each character is 16 bits (two bytes).
VBArray	No direct equivalent	A read-only Visual Basic array. For backward compatibility only.

Data Type Details

See Also

Reference

Concepts

Other Resources