function validate_gb(emailStr) {
  if (document.gb.name.value == ''){
      alert("Please, tell us your name");
      return(false);
  }
	/* begin e-mail validation */	 
	    var emailPat1 = "(@.*@)|(\\.\\.)|(@\\.)|(\\.@)|(^\\.)";
        var emailPat2 = "^.+\\@(\\[?)[a-zA-Z0-9\\-\\.]+\\.([a-zA-Z]{2,3}|[0-9]{1,3})(\\]?)$";
      var matchemArray1 = emailStr.match(emailPat1);
	  var matchemArray2 = emailStr.match(emailPat2);
      if (matchemArray1 == null && matchemArray2 == null) {
         alert("Valid e-mail address is required.");
          return(false);
     }
     /* end e-mail validation */
    if (document.gb.comments.value == ''){
      alert("Please, tell us your comments");
      return(false);
  }
  

  return(true);
}