340
Chapter 2: ActionScript Language Reference
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 2
ActionScript Language Reference
Содержание FLASH MX 2004-ACTIONSCRIPT LANGUAGE
Страница 1: ...ActionScript Language Reference...
Страница 20: ...20 Contents...
Страница 24: ...24 Chapter 1 Introduction...
Страница 39: ...logical AND 39 See also logical NOT inequality strict inequality logical OR equality strict equality...
Страница 145: ...Button onKeyDown 145 See also Button onKeyUp...
Страница 186: ...186 Chapter 2 ActionScript Language Reference See also Camera onActivity Camera setMotionLevel...
Страница 202: ...202 Chapter 2 ActionScript Language Reference See also break default strict equality switch...
Страница 282: ...282 Chapter 2 ActionScript Language Reference See also break continue while...
Страница 329: ...import 329 For more information on importing see Importing classes and Using packages in Using ActionScript in Flash...
Страница 383: ...LoadVars addRequestHeader 383 See also XML addRequestHeader...
Страница 388: ...388 Chapter 2 my_lv load place a valid URL pointing to a text file here...
Страница 402: ...402 Chapter 2 ActionScript Language Reference See also LocalConnection connect LocalConnection send...
Страница 463: ...Microphone setRate 463 See also Microphone rate...
Страница 469: ...Microphone silenceLevel 469 See also Microphone gain Microphone setSilenceLevel...
Страница 471: ...Microphone silenceTimeOut 471 silenceLevel_pb label Activity level inactive See also Microphone setSilenceLevel...
Страница 480: ...480 Chapter 2 ActionScript Language Reference See also Mouse addListener...
Страница 518: ...518 Chapter 2 ActionScript Language Reference See also MovieClip globalToLocal MovieClip localToGlobal...
Страница 529: ...MovieClip globalToLocal 529 See also MovieClip getBounds MovieClip localToGlobal...
Страница 535: ...MovieClip hitTest 535 See also MovieClip getBounds MovieClip globalToLocal MovieClip localToGlobal...
Страница 612: ...612 Chapter 2 ActionScript Language Reference See also MovieClipLoader onLoadStart...
Страница 623: ...NetConnection class 623 See also NetStream class Video attachVideo...
Страница 639: ...NetStream play 639 See also MovieClip attachAudio NetStream close NetStream pause Video attachVideo...
Страница 649: ...Number 649 See also NaN Number class...
Страница 679: ...on 679 on release trace X this _x trace Y this _y stopDrag See also onClipEvent...
Страница 683: ...onUpdate 683 buttonLabel textColor my_mc labelColor...
Страница 788: ...788 Chapter 2 ActionScript Language Reference See also private public...
Страница 847: ...System security allowInsecureDomain 847 See also System security allowDomain System exactSettings...
Страница 1001: ...Video height 1001 my_mc _height my_mc my_video height See also MovieClip _height Video width...
Страница 1022: ...1022 Chapter 2 ActionScript Language Reference See also XML createElement...
Страница 1057: ...XML xmlDecl 1057 See also XML docTypeDecl XML toString...
Страница 1070: ...1070 Chapter 2 ActionScript Language Reference...
Страница 1104: ...1104 Appendix Deprecated Language Elements...