Document uses plugins

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 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

• Source code for Document uses plugins audit
• Unplayable content on mobile devices
• Flash video to HTML5 video