Validate = {
    IsEmpty: function (str) {
        return (str == null) || (str.length == 0);
    },

    IsEmail: function (str) {
        if (Validate.IsEmpty(str)) return false;
        var re = /^[^\s()<>@,;:\/]+@\w[\w\.-]+\.[a-z]{2,}$/i
        return re.test(str);
    },

    // returns true if the string only contains characters A-Z or a-z
    IsAlpha: function (str) {
        var re = /[^a-zA-Z]/g
        if (re.test(str)) return false;
        return true;
    },

    // returns true if the string only contains characters A-Z or a-z
    IsAlphaAndSpace: function (str) {
        var re = /[^a-zA-Z|^\s]/g
        if (re.test(str)) return false;
        return true;
    },

    IsLengthEqual : function(str, len) {
        return str.length == len;
    },

    IsLengthBetween : function (str, min, max) {
        return (str.length >= min) && (str.length <= max);
    }
}