Number Field jQuery plugin

number-field.js

(function ($) {
    var allowedKeys;

    // Allow left, right, tab, backspace, delete and escape
    allowedKeys = [8, 9, 37, 39, 46, 27];

    $.fn.numberField = function () {
        return this.each(function () {
            $(this).on('keypress', function (event) {
                var character;

                character = String.fromCharCode(event.which);
                
                // Only permit allowed keys and 0-9 to be entered
                if (allowedKeys.indexOf(event.keyCode) > -1 || character.match(/([0-9])+/g)) {
                    return true;
                }

                return false;
            });
        });
    }
})(jQuery);