Number.MAX_VALUE and Number.MIN_VALUE define the outer bounds of the Number value set : Introduction « Number Data Type « JavaScript Tutorial

1. JavaScript Tutorial
2. Number Data Type
3. Introduction

All numbers must fall between Number.MAX_VALUE and Number.MIN_VALUE.

When a calculation results in a number greater than Number.MAX_VALUE, it is assigned a value of Number.POSITIVE_INFINITY.

When a calculation results in a number less than Number.MIN_VALUE, it is assigned a value of Number.NEGATIVE_ INFINITY.

If a calculation returns an infinite value, the result cannot be used in any further calculations.

There is a special value for infinity named Infinity.

Number.POSITIVE_ INFINITY has a value of Infinity.

Number.NEGATIVE_INFINITY has a value of -Infinity.

A method can be used to determine if a number is finite.

var iResult = iNum* some_really_large_number;
if (isFinite(iResult)) {
    alert("Number is finite.");
} else {
    alert("Number is infinite.");
}

The perils of Javascript - Number.MIN_VALUE
from lodge.stuart at gmail.com


Just spent some time debugging a problem....

I had a filter set up in my new player code on runsat - and when the filter was disabled I was setting 
the filter limits to Number.MIN_VALUE and Number.MAX_VALUE.

I thought this would be fine because several site like 
http://www.java2s.com/Tutorial/JavaScript/0100__Number-Data-Type/NumberMAXVALUEandNumberMINVALUEdefinetheouterboundsoftheNumbervalueset.htm say things like:

    When a calculation results in a number greater than Number.MAX_VALUE, it is assigned a value of Number.POSITIVE_INFINITY.

    When a calculation results in a number less than Number.MIN_VALUE, it is assigned a value of Number.NEGATIVE_ INFINITY.


However.... this is complete "codswollop" - actually MIN_VALUE is an epsilon value - it's the smallest positive fraction allowed in javascript - so it's not negative - in fact it's almost (but not quite) zero.

Looking around loads of sites contain big info on this!

Yikes!