The isFinite() function determines whether a value is finite, first converting the value to a number if necessary. A finite number is one that's not NaN or ±Infinity. Because coercion inside the isFinite() function can be surprising, you may prefer to use Number.isFinite()....the value to a number if necessary. A finite number is one that's...surprising , you may prefer to use Number.isFinite() . Try it Syntax...