Customizing html.js
Gatsby uses a React component to server render the <head> and other parts of
the HTML outside of the core Gatsby application.
Most sites should use the default html.js shipped with Gatsby. But if you need
to customize your site’s html.js, copy the default one into your source
tree by running:
And then make modifications as needed.
If you need to insert custom HTML into the <head> or <footer> of each page on your site, you can use html.js.
Customizing
html.jsis a workaround solution for when the use of the appropriate APIs is not available ingatsby-ssr.js. Consider usingonRenderBodyoronPreRenderHTMLinstead of the method above. As a further consideration, customizinghtml.jsis not supported within a Gatsby Theme. Use the API methods mentioned instead.
Required props
Note: the various props that are rendered into pages are required e.g.
headComponents, preBodyComponents, body, and postBodyComponents.
Inserting HTML into the <head>
Anything you render in the html.js component will not be made “live” in
the client like other components. If you want to dynamically update your
<head> we recommend using
React Helmet
Inserting HTML into the <footer>
If you want to insert custom HTML into the footer, html.js is the preferred way of doing this. If you’re writing a plugin, consider using the setPostBodyComponents prop in the Gatsby SSR API.
Target container
If you see this error: Uncaught Error: _registerComponent(...): Target container is not a DOM element. it means your html.js is missing the required
“target container”. Inside your <body> you must have a div with an id of
___gatsby like:
Adding custom JavaScript
You can add custom JavaScript to your HTML document by using React’s dangerouslySetInnerHTML attribute.