Detroy and Refresh ad

1. Destroy ad

Ad slots can be destroyed using gladsdk.destroyAdSlots().

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>Test NAM SDK</title>
    <script async src="https://ssl.pstatic.net/tveta/libs/glad/prod/gfp-core.js"></script>
    <script>
      window.gladsdk = window.gladsdk || { cmd: [] };
    </script>
  </head>
  <body>
    <div id="division"></div>
    <button id="destroy">Destroy</button>
    <script>
      window.gladsdk.cmd.push(function () {
        var adSlotInfo = {
          adUnitId: 'WEB_nw_banner-N345765840',
          adSlotElementId: 'division',
        };

        var adSlot = window.gladsdk.defineAdSlot(adSlotInfo);
        window.gladsdk.displayAd(adSlot);
      });

      document.getElementById('destroy').addEventListener('click', function () {
        window.gladsdk.cmd.push(function () {
          var adSlot = window.gladsdk.findAdSlot('division');
          window.gladsdk.destroyAdSlots([adSlot]);
        });
      });
    </script>
  </body>
</html>

If no arguments are passed to gladsdk.destroyAdSlots(), destroy all ad slots.
```
window.gladsdk.destroyAdSlots();
```

2. Refresh ad

Use gladsdk.refreshAdSlots() to destroy existing ad slots and request new ads. (Refresh ad)

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8" />
    <title>Test NAM SDK</title>
    <script async src="https://ssl.pstatic.net/tveta/libs/glad/prod/gfp-core.js"></script>
    <script>
      window.gladsdk = window.gladsdk || { cmd: [] };
    </script>
  </head>
  <body>
    <div id="division"></div>
    <button id="refresh">Refresh</button>
    <script>
      window.gladsdk.cmd.push(function () {
        var adSlotInfo = {
          adUnitId: 'WEB_nw_banner-N345765840',
          adSlotElementId: 'division',
        };

        var adSlot = window.gladsdk.defineAdSlot(adSlotInfo);
        window.gladsdk.displayAd(adSlot);
      });

      document.getElementById('refresh').addEventListener('click', function () {
        window.gladsdk.cmd.push(function () {
          var adSlot = window.gladsdk.findAdSlot('division');
          window.gladsdk.refreshAdSlots([adSlot]);
        });
      });
    </script>
  </body>
</html>

If no arguments are passed to gladsdk.refreshAdSlots(), refresh all ad slots.
```
window.gladsdk.refreshAdSlots();
```

1. Destroy ad​

2. Refresh ad​

1. Destroy ad

2. Refresh ad