I have this code on my website, which displays a popup window with a link, but I'd like to show it only for first-time visitors only. Can someone help me please? I'll be very thankful!

```
window.onload = function() {
    var ABT_closeButton = document.getElementById('ABT_close_button');
    var ABT_float_ads_main_Wrap = document.getElementById('ABT_float_ads_main_Wrap');

    myVar = setTimeout(function() {
        ABT_float_ads_main_Wrap.style.display = 'block';
    }, 1000);

    ABT_closeButton.onclick = function() {
        document.getElementById('ABT_float_ads_main_Wrap').style.display = 'none';
    }
}

```

— Berenica