var eq = function(n1, n2, decimals) { var equal = false; if (decimals === undefined) { decimals = 15; } if (decimals) { var factor = Math.pow(10, decimals); var a = Math.round(n1 * factor) / factor, b = Math.round(n2 * factor) / factor; console.log(n1 + ' => ' + a + " :: " + n2 + ' => ' + b); equal = a == b; } else { equal = n1 == n2; } return equal; } Number.equals=eq; Number.prototype.equals = function(n, d){return eq(this,n,d)};