function isEmpty(str){
  return (str == null) || (str.length == 0);
}
// returns true if the string is a valid email
function isEmail(str){
  if(isEmpty(str)) return false;
  var re = /^[^\s()<>@,;:\/]+@\w[\w\.-]+\.[a-z]{2,}$/i
  return re.test(str);
}

function fnvalidate(f)
{
   if(isEmpty(f.fname.value))
   { 
      alert("Please enter Name.");
	  f.fname.focus();
	  return false;
   }
   if(isEmpty(f.phone.value))
   { 
      alert("Please enter Phone Number.");
	  f.phone.focus();
	  return false;
   }
   var x = f.phone.value;
   if(x!="")
   {
      var valid= "+-()1234567890 ";
		var string = f.phone.value
			var length = string.length;
			for(var i=0;i<=length;i++)
			{
				var substring = string.substr(i,1);
				if(valid.indexOf(substring)== -1)
				{
					alert("Invalid phone No.");
					f.phone.select();
					return(false);
				}
			}
   }
   if(isEmpty(f.email.value))
	{
	  alert("Please enter Email Address.");
	  f.email.focus();
	  return false;
	}
	if(f.email.value!="")
   {
      var x = f.email.value;
	   if(!isEmail(x))
	   {
		  alert("Please enter valid Email Address.");
		  f.email.focus();
		  return false;
	   }
   }
   if(isEmpty(f.message.value))
	{
	  alert("Please enter Query.");
	  f.message.focus();
	  return false;
	}
	
	return true;
}