Currency validation method for the jQuery Validation plugin. Decimal place is optional but if included, it requires 2 places. Also, the dollar sign is optional. EDIT: Original gist did not work with $ sign being optional. This gist adds the optional functionality.

validate-currency.js

      // Validation method for US currency
      $.validator.addMethod("currency", function (value, element) {
            return this.optional(element) || /^\$?(\d{1,3}(\,\d{3})*|(\d+))(\.\d{2})?$/.test(value);
      }, "Please specify a valid amount");