What is unique identity of an Internet connected device IP / MAC?
<p>I am making a script that show popup only one time , then it will never show again on that device.. </p>

<p>How is it possible to do this?</p>

<p>I have already tried by using cookies, but these can be deleted by the user and so the effect is limited.</p>

<p>Another question is what is wholly unique per device, IP Address or MAC Address?</p>
