Can pop-ups cause duplicate content issues in product pages?

[shloy23-294584]

Normally for ecommerce clients that have 100's of products we advise for size guides, installation guides etc to be placed as downloadable PDF resources to avoid huge blocks of content on multiple product pages.

If content was placed in a popup e.g. fancybox, across multiple product pages would this be read by Google as duplicate content?

Examples for this could be:

• An affiliate site with mutiple prices for a product and pop-up store reviews
• A clothing site with care and size guides

What would be the best practice or setup?

[David-Kley]

You could use javascript to load the popup, causing it to not be readable. Search engine spiders cannot read javascript. If you have a dynamic content such as a dynamic menu that uses javascript the search engine spiders will not find and follow the links in that menu therefore, the spider will not be able to index the rest of the pages on your site. Works the same for popups.

There has been some debate on what Google can read within Javascript, but for what you are proposing, I don't see it being likely.

Here is a MOZ post on the subject, complete with a case study:

Can Google Really Access Content in JavaScript? Really?

[Lantec]

I would'nt say so, I would think search engine would be smart enough to work this one out.

Also as @Dave-Kley says above do this with javascript then this is inserted after the search engine has read the page.

[AlanBleiweiss]

Google cannot read ALL JavaScript in every situation. Yet **they most definitely can read at least some of it in some situations. **

The article quoted was from 2012. A LOT has changed since then.

A May 2014 post up in the Google Webmaster Central blog mentioned how they can read it / execute it sometimes, while others they can't, though they do not go into specifics.

A direct quote from Matt Cutts:

“Once that JavaScript has all been loaded, which is the important reason why you should always let Google crawl the JavaScript and the CSS – all those sorts of resources – so that we can execute the page,” he continues. “Once we’ve fetched all those resources, we try to render or execute that JavaScript, and then we extract the tokens – the words that we think should be indexed – and we put that into our index.” source: Webmaster Video April 7, 2014

Oh - and if you block that JS in your robots.txt file, Google MAY respect that, and Google MAY ignore that. While Robots.txt files USED to be a firm "directive", nowadays they're "just one more signal / hint".

Do not assume that in your unique situation Google will or will not find that content, they will or will not see it as duplicate content just because they "may" or "may not" be able to figure out your JavaScript.

Want to avoid that insanity?  Yeah - generate the content you contain in those pop-ups on actual unique URLs that get loaded in those pop-ups.  Then, on those specific URLs, do a noindex,nofollow meta robots tag, AND a canonical tag pointing to the main product description page where that content appears in its primary form.

Or write entirely unique content for those pop-ups.