Here you can find the source of isNumber()
String.prototype.isNumber = function (){ var str = this; return !isNaN(str); }
Number.prototype.isBetween = function isBetween(a, b) { if(a <= this) { return this <= b; return this >= b;
Number.prototype.even = function(){ return (this % 2 === 0); };
var puts = require("sys").puts; Number.square = function(n) { return n * n Number.even = function(n) { return n % 2 == 0 Number.odd = function(n) { return !this.even(n) ...
String.prototype.isNumber = function(){ return !isNaN(this); };
String.prototype.isNumber = function(){ var pattern=/^[+\-]?\d+(.\d+)?$/; flag=pattern.test(this); if(flag) return true; return false;
String.prototype.isNumber = function() return (/^\d+$/.test(this.Trim()));
String.prototype.isNumber = function() try var value = this.toString(); value = value.replace(",",""); if (parseFloat(value)!= value) return false; else ...
String.prototype.isNumeric = function(){ return !isNaN(parseFloat(this)) && isFinite(this);
String.prototype.isNumeric = function() { return !isNaN(parseFloat(this)) && isFinite(this); };