isNaN()
183
isNaN()
Availability
Flash Player 5.
Usage
isNaN(
expression:Object
)
: Boolean
Parameters
expression
A Boolean, variable, or other expression to be evaluated.
Returns
A Boolean value.
Description
Function; evaluates the parameter and returns
true
if the value is
NaN
(not a number). This
function is useful for checking whether a mathematical expression evaluates successfully to a
number.
Example
The following code illustrates return values for the
isNaN()
function:
trace( isNaN("Tree") );
// returns true
trace( isNaN(56) );
// returns false
trace( isNaN(Number.POSITIVE_INFINITY) )
// returns false
The following example shows how you can use
isNAN()
to check whether a mathematical
expression contains an error:
var dividend:Number;
var divisor:Number;
divisor = 1;
trace( isNaN(dividend/divisor) );
// output: true
// The output is true because the variable dividend is undefined.
// Do not use isNAN() to check for division by 0 because it will return false.
// A positive number divided by 0 equals Infinity (Number.POSITIVE_INFINITY).
// A negative number divided by 0 equals -Infinity (Number.NEGATIVE_INFINITY).
See also
NaN
,
Number.NaN
CHAPTER 5
ActionScript Core Language Elements
Содержание FLEX
Страница 1: ...Flex ActionScript Language Reference ...
Страница 8: ......
Страница 66: ...66 Chapter 2 Creating Custom Classes with ActionScript 2 0 ...
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Страница 133: ...break 133 See also for for in do while while switch case continue throw try catch finally ...
Страница 135: ...case 135 See also break default strict equality switch ...
Страница 146: ...146 Chapter 5 ActionScript Core Language Elements See also break continue while ...
Страница 229: ...while 229 i 3 The following result is written to the log file 0 3 6 9 12 15 18 See also do while continue for for in ...
Страница 808: ...808 Chapter 7 ActionScript for Flash ...
Страница 810: ...810 Appendix A Deprecated Flash 4 operators ...
Страница 815: ...Other keys 815 Num Lock 144 186 187 _ 189 191 192 219 220 221 222 Key Key code ...
Страница 816: ...816 Appendix B Keyboard Keys and Key Code Values ...
Страница 822: ...822 Index ...