function valid_feedback()
{
invalidChars_comments = "'\""
invalidChars = "'\""
invalidChars_phone_no = "/\"<>'[]{}%^&zxcvbnm,asdfghjkl:qwertyuiopZXCVBNMASDFGHJKLQWERTYUIOP=_+`~!@#$*"

var full_name = document.feedback.full_name.value
var full_nameLength = document.feedback.full_name.value.length

if(full_nameLength<2 || full_name=="")
	{
	alert("Please enter your name");
	document.feedback.full_name.focus()
	return false
	}
if(full_name!="")
	{
	  for(i=0; i<invalidChars.length; i++)
	  {
	    badChar = invalidChars.charAt(i)
	    if(full_name.indexOf(badChar,0) > -1)
	   {
	   	 alert("Invalid character(s) " + invalidChars + "\n Please check");
		 document.feedback.full_name.focus()
	     return false
	   }
	}
	}
var phone_no = document.feedback.phone_no.value
if(phone_no!="")
	{
	  for(i=0; i<invalidChars_phone_no.length; i++)
	  {
	    badChar = invalidChars_phone_no.charAt(i)
	    if(phone_no.indexOf(badChar,0) > -1)
	   {
	   	 alert("Invalid phone number Please check");
		 document.feedback.phone_no.focus()
	     return false
	   }
	}
	}

var fax_no = document.feedback.fax_no.value
if(fax_no!="")
	{
	  for(i=0; i<invalidChars_phone_no.length; i++)
	  {
	    badChar = invalidChars_phone_no.charAt(i)
	    if(fax_no.indexOf(badChar,0) > -1)
	   {
	   	 alert("Invalid fax number Please check");
		 document.feedback.phone_no.focus()
	     return false
	   }
	}
	}

function validEmail(email)
{
var email = document.feedback.email.value

invalidChars = " /:,;"

  if(email == "")
  {
    return false
  }
  for(i=0; i<invalidChars.length; i++)
  {
    badChar = invalidChars.charAt(i)
    if(email.indexOf(badChar,0) > -1)
   {
      return false
    }
  }

  atPos = email.indexOf("@",1)
  if(atPos == -1)
  {
    return false
  }

  if(email.indexOf("@",atPos+1) > -1)
  {
    return false
  }

  periodPos = email.indexOf(".",atPos)
  if(periodPos == -1)
  {
    return false
  }

  if(periodPos+3 > email.length)
  {
    return false
  }
  return true;
  }


 if(!validEmail(document.feedback.email.value))
{
    alert("Invalid email addsess")
    document.feedback.email.focus()
    document.feedback.email.select()
    return false
}

var comments = document.feedback.comments.value
var commentsLength = document.feedback.comments.value.length

if(comments=="")
	{
	alert("Please enter your comments.");
	document.feedback.comments.focus()
	return false
	}
if(comments!="")
	{
	  for(i=0; i<invalidChars_comments.length; i++)
	  {
	    badChar = invalidChars_comments.charAt(i)
	    if(comments.indexOf(badChar,0) > -1)
	   {
	   	 alert("Invalid character(s) " + invalidChars_comments + "\n Please check");
		 document.feedback.comments.focus()
	     return false
	   }
	}
	}
if(commentsLength>250)
	{
	alert("Sorry, your comments must less then 249 chrs.");
	document.feedback.comments.focus()
	return false
	}
var agreed = false;
for (counter = 0; counter < document.feedback.fg.length; counter++)
	{
		if (document.feedback.fg[0].checked || document.feedback.fg[1].checked )
		agreed = true; 
	}
if (!agreed)
	{
		alert("Message type:\nPlease choose Feedback or Guestbook.")
		return false;
	}
}