What is the !! operator in JavaScript?

Posted by Hexagon Theory on Stack Overflow See other posts from Stack Overflow or by Hexagon Theory
Published on 2009-04-24T08:13:58Z Indexed on 2010/04/07 2:23 UTC
Read the original article Hit count: 310

Filed under:

JavaScript

|

operators

I've seen code that seems to use an operator I don't recognize, in the form of two exclamation points, like so: !!. Can someone please tell me what this operator does?

© Stack Overflow or respective owner

Related posts about JavaScript

CHAT ROOMs 7 by 6

as seen on Stack Overflow - Search for 'Stack Overflow'
I am looking for chatroom on one page with 7 loggedin users and 6+rows for say 42 users.these users will keep on adding wthnew users.Need urgent help.A PRETTY UNUSUAL Q FOR MOST OF U.What is MORE REQ new features: Usernames are unique to users currently chatting You can see a "currently chatting"… >>> More
Integrating JavaScript Unit Tests with Visual Studio

as seen on Stephen Walter - Search for 'Stephen Walter'
Modern ASP.NET web applications take full advantage of client-side JavaScript to provide better interactivity and responsiveness. If you are building an ASP.NET application in the right way, you quickly end up with lots and lots of JavaScript code. When writing server code, you should be writing… >>> More
Has Javascript developed beyond what it was originally designed to do?

as seen on Programmers - Search for 'Programmers'
I've been talking with a friend about the purpose of Javascript, when and how it should be used, etc. He quoted that: JavaScript was designed to add interactivity to HTML pages [...] JavaScript gives HTML designers a programming tool HTML authors are normally not programmers… >>> More
PHP, javascript, single quote problems with IE when passing variable from ajax post to javascript fu

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi! I have been trying to get this to work for a while, and I suspect there's an easy solution that I just can't find. My head feels like jelly and I would really appreciate any help. My main page.php makes a .post() to backend.php and fetches a list of cities which it echoes in the form of: <li… >>> More
Javascript in XSL that is loaded by Javascript

as seen on Stack Overflow - Search for 'Stack Overflow'
Is there anyway to have javascript run when a XSL sheet has been applied to an XML file by Javascript? I am using a JQuery plugin to apply the sheet to the xml but the javascript that is located inside of the XSL file will not run. I put the Javascript at the bottom of the file and it still does… >>> More

Related posts about operators

How do boost operators work?

as seen on Stack Overflow - Search for 'Stack Overflow'
boost::operators automatically defines operators like + based on manual implementations like += which is very useful. To generate those operators for T, one inherits from boost::operators<T> as shown by the boost example: class MyInt : boost::operators<MyInt> I am familiar with the CRTP… >>> More
Use Comparison Operators in SQL to Remove/Return Columns with Null Values

as seen on Internet.com - Search for 'Internet.com'
When you use the comparison operators in SQL with the Where clause, you can remove the columns with null values. >>> More
Use Comparison Operators in SQL to Remove/Return Columns with Null Values

as seen on Internet.com - Search for 'Internet.com'
When you use the comparison operators in SQL with the Where clause, you can remove the columns with null values. >>> More
How do I overload an operator for an enumeration in C#?

as seen on Stack Overflow - Search for 'Stack Overflow'
I have an enumerated type that I would like to define the , <, =, and <= operators for. I know that these operators are implictly created on the basis of the enumerated type (as per the documentation) but I would like to explictly define these operators (for clarity, for control, to know how… >>> More
Which are the fundamental stack manipulation operations?

as seen on Programmers - Search for 'Programmers'
I'm creating a stack oriented virtual machine, and so I started learning Forth for a general understanding about how it would work. Then I shortlisted the essential stack manipulation operations I would need to implement in my virtual machine: drop ( a -- ) dup ( a -- a a ) swap ( a b -- b a ) rot… >>> More