Home > Developer > Web Develop

In JS when the IF condition is null/undefined/0/nan/"" expression, all is interpreted as false, also true

Source: Internet
Author: User
Developer on Alibaba Coud: Build your first app with APIs, SDKs, and tutorials on the Alibaba Cloud. Read more ＞

Boolean expression

An expression with a value of true or false . Non-Boolean expressions can also be converted to a Boolean value if desired, but the following rules are followed:

  • All objects are treated as true.
  • The string is treated as false when and only if the string is empty.
  • null and undefined are treated as false.
  • When and only if the number is zero, the number is treated as false.

In JS when the IF condition is null/undefined/0/nan/"" expression, all is interpreted as false, also true

This article is an English version of an article which is originally in the Chinese language on aliyun.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to info-contact@alibabacloud.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

Related Keywords:
if true false javascript if true false if true or false can expression true or false true false in javascript if not true then false laptop computer is also called
Related Article
Jwt+asp.net MVC timestamp prevents replay attacks
HTTP status code: 301, 302 redirect
HTTP returns the difference between 301 and 302 in the status...
About HTTP return Codes 301, 302 differences with SEO

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

What's Trending
Top 10 Tags
datastax versions naming convention zookeeper client class definition md5 microsoft sql server 2005 data structures exception handling error handling
Top 10 Keywords
microsoft download center down wordpress address url site address url wordpress address url windows installer 4 0 download 302 not found web address url definition site address url wordpress db2 integer mac os installation step by step pdf abbreviation for return

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

Get Started for Free

  • Sales Support

    1 on 1 presale consultation

    Chat Contact Sales

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

    Open a Ticket

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.

    Learn More