11.7. WMLScript typeof
Operator - Finding Data Types of Variables
As
mentioned previously in the "WMLScript
Data Types" section of this WMLScript tutorial, there is
only one type of variable in WMLScript, which is var. A variable can
contain a value of any of the five primitive data types -- Boolean,
integer, float, string and invalid. If you want to determine the data
type of the value stored in a variable, you can make use of the
typeof operator. The typeof operator returns an integer
that indicates the data type of a value.
WMLScript
data type
|
Return
value of the typeof operator
|
Integer
|
0
|
Float
|
1
|
String
|
2
|
Boolean
|
3
|
Invalid
|
4
|
The
following WMLScript example demonstrates how to use the typeof
operator to find the data type of the value stored in a variable:
var
number1 = 100; var number2 = 1.11; var x = typeof number1; var
y = typeof number2;
After
the execution of the above script, the x variable contains the
value 0 (indicates that an integer is stored in the number1
variable) while the y variable contains the value 1 (indicates
that a floating-point number is stored in the number2
variable).
The
operand of the typeof
operator does not have to be a variable. For example:
var
x = typeof (100 / 0); var y = typeof (10 / 3); var z = typeof
"WMLScript Tutorial";
After
executing the above script, x contains 4 (invalid type), y contains 1
(float type) and z contains 2 (string type).
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