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()
{
  if        (Is_Blank_String (document.C0mments_Form.author.value))
  {
    alert ("Name is required");
    return false;
  }

  if        (!Is_Blank_String (document.C0mments_Form.email.value)
  &&
  !Is_eMail (document.C0mments_Form.email.value))
  {
    alert ("E-mail is incorrect");
    return false;
  }

  if        (Is_Blank_String (document.C0mments_Form.c0mments.value))
  {
    alert ("Error: Message is empty !");
    return false;
  }

  if        (document.C0mments_Form.c0mments.value.length > 5000)
  {
    alert ("Your message is too long. Please, divide it into parts or cut.");
    return false;
  }

  return true;
}