11.8. WMLScript isvalid Operator: Finding if a Variable is of the Invalid Data Type
WMLScript's isvalid operator is used to find out whether a variable is of the invalid data type. It returns the Boolean value true if the variable is not of the invalid data type, otherwise it returns false. The following WMLScript code demonstrates how to use the isvalid operator:
var
number1 = 100;
var number2 = 100 / 0;
var x = isvalid
number1;
var y = isvalid number2;
After execution, the number2 variable contains an invalid value. The variables x and y contain true and false respectively.
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Contents at a Glance (Click Here for Full Table of Contents)
- 1. WMLScript Introduction
- 2. Hello World WMLScript Example
- 3. Compiling WMLScript Code
- 4. WMLScript Language Rules
- 5. Defining WMLScript Functions
- 6. Calling WMLScript Functions
- 7. WMLScript Variables
- 8. WMLScript Data Types
- 9. WMLScript Variables Vs WML Variables
- 10. Passing Arguments to Functions By Value and By Reference
- 11. WMLScript Operators
- 12. WMLScript Conditional Statements
- 13. WMLScript Looping Statements
- 14. WMLScript Standard Libraries Overview
- 15. WMLScript WMLBrowser Standard Library
- 16. WMLScript Dialogs Standard Library
- 17. WMLScript String Standard Library
- 18. WMLScript Float Standard Library
- 19. WMLScript Lang Standard Library
- 20. WMLScript URL Standard Library
- 21. WMLScript Example: Validating Form Data
