var regexp = new RegExp("^(" + formatList[i + i] + ")$");

Brackets is every important, or it will come out unexpect results. For example, for ([1-9]\d(\.\d\d?)?)|(\d(\.\d\d?)?)|(100(\.00?)?),

var regexp = /^([1-9]\d(\.\d\d?)?)|(\d(\.\d\d?)?)|(100(\.00?)?)$/;
alert(regexp.test("27.8d"));

var regexp = /^(([1-9]\d(\.\d\d?)?)|(\d(\.\d\d?)?)|(100(\.00?)?))$/;
alert(regexp.test("27.8d"));

will come out with true and false, in which the former is incorrect!