Is it possible that the focus of SEO in some browsers? For my site, I worked hard on browsers such as Firefox, IE and Chrome for SEO. I noticed that Firefox is the best browser for seo than anyone else. I think it is because Firefox comes with some SEO tools that are on hand to complete the process. These include the auditor site pagerank, Alexa, suggestion tool keyword competitive research, etc tool if you are looking to optimize your site, I suggest you use these tools.