function blank_test(f)
	 {
	 if (f.name.value=="")
		 {
				 alert("Please write your name..");
				 f.name.focus();
				 return false;
		 }
	 if (f.tel.value=="")
		 {
				 alert("Please write your phone..");
				 f.tel.focus();
				 return false;
		 }
	 if (f.email.value=="")
		 {
				 alert("Please write your e-mail..");
				 f.email.focus();
				 return false;
		}
 	 if (f.email.value != "")
		 {
		    if ((f.email.value.indexOf ('@') == -1) || (f.email.value.indexOf ('.') == -1))
				{
				 alert("Please write a valid e-mail..");
				 f.email.focus();
			      return false;
				}
		}
	 if (f.msg.value=="")
		 {
				 alert("Please write your message..");
				 f.msg.focus();
				 return false;
		 }
}