Document uses plugins

Document uses plugins

Appears in: SEO audits

Search engines often can't index content that relies on browser plugins, such as Java or Flash. That means plugin-based content doesn't show up in search results.

Also, most mobile devices don't support plugins, which creates frustrating experiences for mobile users.

How the Lighthouse plugins audit fails #

Lighthouse flags pages that use plugins:

Lighthouse audit showing document uses plugins

Lighthouse checks the page for elements that commonly represent plugins:

  • embed
  • object
  • applet

Lighthouse then flags an element as a plugin if its MIME type matches any of the following:

  • application/x-java-applet
  • application/x-java-bean
  • application/x-shockwave-flash
  • application/x-silverlight
  • application/x-silverlight-2

Lighthouse also flags elements that point to a URL with a file format that is known to represent plugin content:

  • swf
  • flv
  • class
  • xap

Don't use plugins to display your content #

To convert plugin-based content to HTML, refer to guidance for that plugin. For example, MDN explains how to convert Flash video to HTML5 video.

Resources #

Each SEO audit is weighted equally in the Lighthouse SEO Score, except for the manual Structured data is valid audit. Learn more in the Lighthouse Scoring Guide.

Last updated: Improve article