!== and === are identity operators. It is a good idea to use them instead of the equality operators (!= and ==) unless you know why you would want to use equality (and the possible type coercion) over identity. Probably the biggest gotcha with equality is with falsy values (false, 0, undefined, ""/empty string, null and NaN). The truthy / falsy issue is probably what bit you Rob.
It may be worth reading a bit of Douglas Crockford's ideas about javascript if you are trying to figure out identity and equality operators: http://javascript.crockford.com/code.html And here is something about truthy and falsy: http://developer.mozilla.org/en/docs/A_re-introduction_to_JavaScript#Other_types Ian On 8/2/07, Rob Desbois <[EMAIL PROTECTED]> wrote: > I had a discussion on the use of the === and !== operators recently on this > list, my opinion was, and still is, that unless you explicitly WANT to allow > type conversion, you should be using these. Only use == and != if you really > want type conversion. > > It's bitten me once, although I can't for the life of me remember how, but > it involved lots of in-depth debugging and head-scratching to find the > problem. I'm more wary now and think that these operators are the way to go. > > --rob > > > On 8/2/07, Sam Collett <[EMAIL PROTECTED]> wrote: > > > > I don't think many actually use !== (and when you would want to use > > it) and many sites that show usage of operators don't cover !== (but > > do have ===). > > > > 3 != '3' false > > 3 !== '3' true > > 3 == '3' true > > 3 === '3' false > > > > > > On Aug 1, 9:33 pm, "Michael Geary" <[EMAIL PROTECTED]> wrote: > > > > I...cannot figure how what the heck === is. > > > > > > I see that Jake answered your question, but just for next time... > > > > > > You may have tried a Google search for "javascript ===" and been > > > disappointed to find it returned no useful results (because Google seems > to > > > ignore the === in the search). > > > > > > The key thing to know is that ===, like most special symbols in > JavaScript > > > such as + and -, is an operator. Now you can do a more productive Google > > > search: > > > > > > http://www.google.com/search?q=javascript+operators > > > > > > This will help when you run into !== and wonder what the heck *that* one > is. > > > :-) > > > > > > -Mike > > > > > > > > -- > Rob Desbois > Eml: [EMAIL PROTECTED] > Tel: 01452 760631 > Mob: 07946 705987 > "There's a whale there's a whale there's a whale fish" he cried, and the > whale was in full view. > ...Then ooh welcome. Ahhh. Ooh mug welcome.
