function validate_required(field,alerttxt)
{
	with (field)
	{
		if (value==null||value=="")
		  {alert(alerttxt);return false;}
		else {return true}
	}
}

function validate_email(field,alerttxt)
{
	with (field)
	{
		apos=value.indexOf("@");
		dotpos=value.lastIndexOf(".");
		if (apos<1||dotpos-apos<2) 
		  {alert(alerttxt);return false;}
		else {return true;}
	}
}

function validate_form(thisform)
{
	with (thisform)
	{
		if (validate_required(visitor,"Please fill the Name field!")==false)
		  {visitor.focus();return false;}
		if (validate_required(visitormail,"Please fill the Email field!")==false)
		  {visitormail.focus();return false;}
		if (validate_required(notes,"Please fill the Mail Message field!")==false)
		  {notes.focus();return false;}
		if (validate_email(visitormail,"Please enter a valid email address")==false)
		  {visitormail.focus();return false;}		
	}
}