Google rolling Out Faster JavaScript to 'Boost in Speed' of AdSense Ads (Asynchronous AdSense)

Google today announced a major boost in speed for AdSense publishers worldwide. The best part is, you don't need to make any changes to your code or account -- the faster load time has kicked into gear for everyone automatically, so your visitors will experience a noticeable improvement in the speed of your webpages! "We've […]

Google today announced a major boost in speed for AdSense publishers worldwide. The best part is, you don't need to make any changes to your code or account -- the faster load time has kicked into gear for everyone automatically, so your visitors will experience a noticeable improvement in the speed of your webpages!

"We've now developed a new ads delivery technique to improve the speed of websites that display AdSense ads, so that it doesn't slow down your page content. Over the past few days we've been rolling out a new and improved version of show_ads.js, the piece of JavaScript used by more than two million publishers to put AdSense ads on their web pages. The new show_ads is small and fast, built so that your browser can turn its attention back to its main task -- working on the rest of the web page -- ASAP. This change is now making billions of web pages every day load faster by half a second or more," explains Google.

"The old show_ads did lots of work: loading additional scripts, gathering info about the web page it was running on, and building the ad request to send back to Google. The new show_ads has a different job. It creates a friendly (same-origin) iframe on the web page, and starts the old script with a new name, show_ads_impl, running inside that iframe. The _impl does all the heavy lifting, and in the end the ads look exactly the same. But there's a substantial speed advantage: many things happening inside an iframe don't block the web browser's other work."

"How much of an effect this has depends on context: a page with nothing but ads on it isn't going to get any faster. But on the real-world sites we tested, the latency overhead from our ads is basically gone. Page load times with new asynchronous AdSense implementation are statistically indistinguishable from load times for the same pages with no ads at all."

And what if you've built a page that loads AdSense ads and then manipulates them in exotic ways not compatible with friendly iframes? You can set "google_enable_async = false" for any individual ad slot to revert to old blocking behavior. But if your site loads ads in some tortuous way because you were looking for latency benefits, consider giving the straightforward invocation of show_ads.js a whirl," Google added.

"These dynamically-populated friendly iframes are finicky beasts. At this time, we're deploying globally for users of Google Chrome, Mozilla Firefox and Microsoft Internet Explorer 8 and will be expanding the list of browsers that benefit from this speed-up soon."

[Source]