Element.addMethods(['input'],
    {
      isPositiveInteger: function(p_el) {
        return /^\d+$/.test(p_el.getValue().strip());
      }
    , isPositiveDecimalNumber: function(p_el) {
        return /^\d*(\.\d+)?$/.test(p_el.getValue().strip());
      }
    , isEmailAddress: function(p_el) {
        //return /^[\w(\.\w)]+@\w[\.\w]+$/.test(p_el.getValue().strip());
        return /^[^@]+@[^@\.]+(\.[^@\.]+)+$/.test(p_el.getValue().strip());
      }

    });