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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