Thanks, Liam and Brett, for the explanations! Rick
-----Original Message----- From: jquery-en@googlegroups.com [mailto:jquery...@googlegroups.com] On Behalf Of Brett Ritter Sent: Tuesday, August 11, 2009 1:00 PM To: jquery-en@googlegroups.com Subject: [jQuery] Re: How to specify a default value... On Tue, Aug 11, 2009 at 12:10 PM, Rick Faircloth<r...@whitestonemedia.com> wrote: > What I still don't understand is even how this logic works: > > if ( row[19] ) { > row[19] > } else { > N/A > } The key part is "if( row[19] )". row[19] is being evaluated for _truth_. Javascript defines (I believe) truth to be "non-false", and false is defined as any of: undefined null 0 "0" (a string with value zero..I think. I may be channeling Perl here) "" (empty string) false (boolean value) So if you are trying to provide a default value in the case of null only, then you should check for null because any of the other "false" (non-null) values will give you your provided default instead. The ( test ? return if true : return if false ) construct allows a full test, so: ( row[19] == null ? "default" : row[19] ) works. If you want to look up more about this sort of construct, it's called the "ternary operator" and exists in many programming languages. -- Brett Ritter / SwiftOne swift...@swiftone.org
