 |
Chapter 21 JavaScript Reference |
 |
Navigator 3.0; Unix platforms in Navigator 2.0; implemented but nonfunctional in Internet Explorer 3.0
isNaN(x)
The value to be tested.
true if x is the reserved value NaN (not-a-number); false if x is a legal number, string, or any other type.
isNaN() tests its argument to determine whether it is the reserved value NaN, which represents an illegal number (such as the result of division by zero). This function is required, because comparing a NaN with any value, including itself, always returns false, so it is not possible to test for NaN with the == operator.
The NaN value is not implmemented in Internet Explorer 3.0, so isNaN() always returns false on that platform.
A common use of isNaN() is to test the result of parseFloat() and parseInt() to determine if they represent legal numbers. You can also use it to check for arithmetic errors, such as division by zero.
|
 |
|
| Image.width |  |
java |
| file: /Techref/language/java/script/definitive/refp_176.htm, 5KB, , updated: 2019/10/14 15:00, local time: 2024/11/20 10:03,
18.189.188.8:LOG IN
|
| ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions? <A HREF="http://linistepper.com/Techref/language/java/script/definitive/refp_176.htm"> [Chapter 21] Reference: isNaN()</A> |
| Did you find what you needed? |