Community Learn Tools Library Leisure
search
English
Home > Web Front-end > JS Tutorial > js中，只有三种情况变量值是fasle

js中，只有三种情况变量值是fasle

WBOY
Release： 2016-06-01 09:55:07
Original
1332 people have browsed it

第一， 0是false，这个大家都知道。

注意：var a="0"; 变量a的值是true;

第二，当一个变量未定义时，是undefined类型，undefined类型是false.

第三，NaN是false.

js中，只有这三种情况是false，其他的全部是true.

Related labels：
false true variable
source：php.cn
Previous article：js遍历数组的两种方法 Next article：js parseInt 将字符串的开头几个数字转化为int
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Latest Issues
How to display the mobile version of Google Chrome Hello teacher, how can I change Google Chrome into a mobile version?
From 2024-04-23 00:22:19
0
9
1588
What is the format of the variables in the return value? I am a new learner of php. I found a piece of code: if($x<time()){return[false,'error']...
From 2024-04-06 21:55:20
0
1
778
Dynamically modify inline CSS styles in Javafx I'm trying to change the background image of a pane when the application is maximized. My ...
From 2024-04-06 20:57:16
0
1
487
SQL Count() also requires 0 I have only one table and I want to count each entry of a tag that starts with 0. Now I tr...
From 2024-04-06 19:48:53
0
1
449
MySQL: "Select text from... as <variable here or subquery>" I have the following table with the following data: id text language 1 german text german ...
From 2024-04-06 19:25:54
0
2
529
Related Topics
More>
Popular Recommendations
Popular Tutorials
More>
Related Tutorials
Popular Recommendations
Latest courses
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template