Have any of you guys successfully gotten this to work? I've seriously been working on it for a month now, and I have very little hair left! But I honestly can't even tell if it's working.

The best I can tell, the only way to do it is by using DFP:

[support.google.com...]

I'm also using this is a separate guide:

[igorkromin.net...]

I have the Infinite Scroll working (I have other threads on that, if you care to figure out how I managed it), but the ads still give me a hard time. I'm not getting any errors or anything, just blank spaces.

But here's the kicker. After several hours of coding. I had ONE ad to show up, but no more throughout the scroll. But the top ad is slightly different from the rest, so I'm not even sure if I could just copy that code throughout. And after I refreshed I didn't see any more ads, anyway, so for all I know it could be that Adsense isn't showing me any ads because I'm working in a sandbox (a subdomain of a live site).

So I really need some advice from somebody that's been there.

Here's the code I've finally settled on:

<script async="async" src="https://www.googletagservices.com/tag/js/gpt.js"></script>

<script>
var googletag = googletag || {};
googletag.cmd = googletag.cmd || [];

var slot = new Array();
var horizontal_ad;

googletag.cmd.push(function() {

 // Mimic a responsive banner
 horizontal_ad = googletag.sizeMapping().
 addSize([800, 0], [1, 1]). // desktop, > 800x0 don't show anything
 addSize([728, 0], [728, 90]). // tablet, > 728x0 show 728x90
 addSize([320, 0], [320, 50]). // mobile, > 320x0 show 320x50
 build();

 // This one shows by default, outside of Infinite Scroll, and works... sometimes.
 // In the real code I also have a slot[1] defined for a footer, but it's not relevant 
 // to this problem so I left it out
 slot[0] = googletag.defineSlot('/xxxx/Mobile_Tablet',
 [[728, 90], [320, 50]], 'data_b_0').
 defineSizeMapping(horizontal_ad).
 addService(googletag.pubads());

 googletag.pubads().enableSingleRequest();
 googletag.pubads().disableInitialLoad();
 googletag.enableServices();
});
</script>

// Set somewhere in the header; $data_b is in PHP
$data_b = 1;

// Later, inside of the Infinite Scroll, using PHP
for ($i = 0; $i < 10; $i++) {
 // Show a banner every 5th loop
 if ($i > 0 && ($i / 5 == intval($i / 5))) {
 $data_b++;

 // This code seemed to work, but just the one time. I tried using it on every
 // iteration instead of just the first one, but I just had blank ads after that
 if ($data_b == 2)
 echo <<<EOF
<div id="data_b_$data_b" class="h_banner">
 <script>
 googletag.cmd.push(function() {

 // Identical to slot[0] except for the 'data_b_$data_b'
 slot[$data_b] = googletag.defineSlot('/xxxx/Mobile_Tablet',
 [[728, 90], [320, 50]], 'data_b_$data_b').
 defineSizeMapping(horizontal_ad).
 addService(googletag.pubads());

 googletag.display('data_b_$data_b');
 googletag.pubads().refresh([slot[$data_b]]);
 });
 </script>
</div>

EOF;

 else
 // This is based on the information from the second guide, not the Adsense
 // support page. It's basically identical, but includes a "newAd" section that I
 // don't understand
 echo <<<EOF
<div id="data_b_$data_b" class="h_banner">
 <script>

 // I have no idea what's going on with newAd. This is almost verbatim from the
 // sample, but the sample never used the newAd variable after newAd.find(), so 
 // I don't understand it at all. <div id='data_b_0'> uses slot[0], though, so that's 
 // what (I think) I'm trying to clone
 var newAd = $('#data_b_0').clone().appendTo('#data_b_$data_b').show();
 newAd.find('.h_banner').attr('id', 'data_b_$data_b');

 // This is identical to the one above
 googletag.cmd.push(function() {
 slot[$data_b] = googletag.defineSlot('/xxxx/Mobile_Tablet',
 [[728, 90], [320, 50]], 'data_b_$data_b').
 defineSizeMapping(horizontal_ad).
 addService(googletag.pubads());

 googletag.display('data_b_$data_b');
 googletag.pubads().refresh([slot[$data_b]]);
 });
 </script>
</div>

EOF;
 }
}

I'm half convinced that it would work just fine if I went live with it (minus the "else" section entirely) and gave it legit traffic, but I just don't know. And AFAIK there's not a way to list a backup ad with DFP, so I can't even see if that's loading for testing >:-(

ANY suggestions would be greatly appreciated! While I still have a little hair that I haven't pulled out yet, anyway :-P