Google: Top Problems We See With Dynamic Serving Mobile Implementation

Google is providing mobile optimization tips all this week on their Google+ channel and as expected, most of them are pretty basic stuff.

For example, yesterday afternoon, Google shared that when you do dynamic serving you want to (A) let Googlebot know that the content varies based on user agent by using the Vary HTTP header: Vary: User-Agent and (B) treat Googlebot like you would treat any other device. For example, if Googlebot identifies itself as an iPhone, treat it like an iPhone. Yes, basic stuff.

But then Google's Pierre Far shared on Google+ a few problems they typically see around how webmasters implement dynamic serving. He said here are the three solutions for those top three problems they see:

1. For JavaScript, you can use simple code (an if statement) embedded in the HTML to fetch different JS files.

2. For CSS, you can use different media queries to download the right CSS file.

3. For images, you can use the element or srcset attributes as described here: http://responsiveimages.org. Granted browser support is not 100% yet, but it's quickly coming along, so prepare to benefit from this soon!

So if you go this route, make sure you handle these appropriately even though they are basic - many mess up here.

Forum discussion at Google+.