Does Google or other search engines run JavaScript?

Question

I'm just wondering if Google or other search engines will execute JavaScript on your web page. For example, if you set a title tag using JavaScript, does the Google search engine see this?

Answer 1

For SEO purposes, some experiments have been conducted that show that at least large players (like Google) can follow and execute some simple JavaScript. They avoid covert redirects, etc., but some basic manipulations with the content seem to go through. (I don’t have a link convenient for Google itself either confirming or denying it, these are just different messages that I encountered when doing this before.)

However, this is usually considered unreliable. If SEO is done for any important purpose, don't rely on spiders indexing a lot of dynamic content.

Actually a very good (in my opinion, one way or another) answer to a very similar question here. What I like about this answer is how it breaks down the steps to create good, indexable, and the best of all supported web pages with proper separation of problems. Adhering to as much of this process as possible will result in good SEO, good accessibility, and good design skills in general.

Answer 2

Yes, Google does Javascript. How much is a moving target.

Google completed some Javascript as early as 2011: http://searchengineland.com/google-can-now-execute-ajax-javascript-for-indexing-99518

This 2012 article shows some experiments on what Google Javascript did and didn't do at the time: http://moz.com/ugc/can-google-really-access-content-in-javascript-really

In May 2014, Google publicly announced that they were running Javascript: http://googlewebmastercentral.blogspot.com/2014/05/understanding-web-pages-better.html Although this post says that Google has improved, there is no publicly available information about what Google Javascript does and doesn't do, but they seem to be at least as good as they were in 2012.

Answer 3

Google will not see your title because it is installed on the client side.

If you want dynamic titration, just enter it from the server.

Answer 4

I am sure that they do not. However, you can see for yourself: Google has a tool that will show you your page because it sees it as http://www.google.com/webmasters/

Answer 5

if the text is in onpage javascript, Google will see the text. but it will not be considered as the text of the title element.

but hey, it's pretty easy to check. just do it. wait two days. if you then host your site with the site: .... look at that in the title. if it is there then the answer will be yes: google sees it, if not: no google no. it's easy to check.

(ps: my money: no)

Answer 6

We need to remember that JavaScript is a client language and always runs from the client side. If all the headers or content via javascript will then be displayed from the client side, and I doubt it will be displayed in a Google search (meanwhile, if displayed in .html, then yes).

If I’m right, since the last meta tags are “fuel for the search engine”, and it has links to SEO, where regular robots should be written to crawl on your site.