admin管理员组

文章数量:1337106

I expected !!"false" to return false i.e. !"false" would return true, so !!"false" would return "false", but when I tested it in the console, !!"false" returned true.

Why didn`t things happen as expected?

I expected !!"false" to return false i.e. !"false" would return true, so !!"false" would return "false", but when I tested it in the console, !!"false" returned true.

Why didn`t things happen as expected?

  • javascript
Share Improve this question edited Mar 18, 2011 at 4:57 mjmitche asked Mar 18, 2011 at 4:39 mjmitchemjmitche 2,0676 gold badges25 silver badges31 bronze badges 1
  • Possible duplicate of How can I convert a string to boolean in JavaScript?. Voted to close. – MAK Commented Mar 18, 2011 at 4:42
Add a ment  | 

2 Answers 2

Reset to default 12

"false" is a non-empty string, which evaluates to true. Hence !"false" is false and !!"false" is true. You were probably thinking of !!false.

The reason this is occurring because anything other than an empty string will return true.

本文标签： JavaScript quotfalsequotStack Overflow

版权声明：本文标题：JavaScript !!"false" - Stack Overflow 内容由网友自发贡献，该文观点仅代表作者本人， 转载请联系作者并注明出处：http://www.betaflare.com/web/1742242793a2438937.html， 本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌抄袭侵权/违法违规的内容，一经查实，本站将立刻删除。