3 ms·
isNaN will return true for NaN and all values that coerce to it. The equals check will test ONLY for NaN itself: var x = "a"; isNaN(x); // true (x === x) ===
by grayrest 14y ago
isNaN will return true for NaN and all values that coerce to it. The equals check will test ONLY for NaN itself:
var x = "a";
isNaN(x); // true
(x === x) === false // false
x = NaN
isNaN(x); // true
(x === x) === false // true