Does Javascript Affect Ranking?

Almost all SEO's agree that using too much javascript can harm your rankings and might confuse the search engines.

Is it true? We decided to answer this extremely simple question for the two leading search engines using a simple statistical analysis.

The methodology: I gathered the results of the queries that were naturally performed last month by myself and three associates using the two leading search engines and analyzed them. I had to visit each page and check the HTML source code to see if javascript was being used. I counted the number of pages found that utilized javascript for the first 8 rankings. The results for each of the two leading search engines were kept separate so that we could discover any differences between the two leading search engines for this factor.

The resulting graphs show the number of pages utilizing javascript for each ranking. The Y-axis shows the number of pages found utilizing javascript, while the X-axis shows rankings 1 through 8. Here are the graphs for each of the two leading search engines:

The result is very conclusive and very surprising. Both leading search engines rank pages that utilize javascript higher than pages that do not utilize javascript. This is another example of how the guesses of the SEO community are often just that... guesses... They have a 50% chance of being correct on any particular factor. In this case, the majority of the SEO community guessed wrong.

Notes:

1. There was no exercise to attempt to isolate different keywords. I merely took a random sampling of the queries performed by myself and three associates during the month.

Conclusion:

Pages which utilize javascript rank higher than pages that do not utilize javascript on both of the leading search engines.

This is merely a correlation study, so it cannot be determined from this study whether the leading search engines purposefully entertain this factor or not. The actual factors used may be far distant from the factor we studied, but the end result is that these search engines do, in fact, rank pages with javascript higher than pages without javascript in the study.

Jon Ricerca is one of the leading researchers and authors of the Search Engine Ranking Factor (SERF) reports at SearchEngineGeek.com. For access to the other SERF reports, please visit: http://www.SearchEngineGeek.com