function  Is_eMail(Test_String)
{
  if (/^^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/.test (Test_String))
    return true;
  else
   return false;
}

function  Is_Blank_String(Test_String)
{
  return        !/\S/.test (Test_String);
}
function Validate()
{
// document.Feedback_Form.add_feedback.disabled = true;

if (Is_Blank_String (document.Feedback_Form.author.value))
{
   alert ("Name is required");
   return false;
}

if (!Is_Blank_String (document.Feedback_Form.email.value)
&&
!Is_eMail (document.Feedback_Form.email.value))
{
    alert ("E-mail is incorrect");
   return false;
}

if        (Is_Blank_String (document.Feedback_Form.comments.value))
{
	alert ("Error: Message is empty !");
	return false;
}

if        (document.Feedback_Form.comments.value.length > 3000)
{
	alert ("Your message is too long. Please, divide it into parts or cut.");
	return false;
}

return true;
}