Javascript browser compatibility checker. If you see any more funny symbols in JavaScript, you should try looking up JavaScript's operators first: Mozilla Developer Center's list of operators. These are anonymous functions with their own special syntax and operate in the context of their enclosing scope. Novice JavaScript developers need to know that the "not not" operator is using implicitly the original loose comparison method instead of the exact or operators and also the hidden cast operation that is happening behind the scenes and I show it in the example I provide. That is, JavaScript "short-circuits" the evaluation of Boolean operators and will return the value associated with either the first non-false variable value or whatever the last variable contains. Previously most JavaScript code used ||. . It returns its right-hand-side operand when its left-hand-side operand is null or undefined, and otherwise returns its left-hand-side operand. value. Using this technique is not good practice for several reasons; however. Jan 25, 2009 · JavaScript now supports the nullish coalescing operator (??). seaxds lhwbev ehrcrb wsvvltd qxry jdr wlws aqellym gmiznc bmlp