loadCSS

Referencing CSS stylesheets with link[rel=stylesheet] or @import causes browsers to delay page rendering while a stylesheet loads. When loading stylesheets that are not critical to the initial rendering of a page, this blocking behavior is undesirable. The pattern below allows us to fetch and apply CSS asynchronously. If necessary, this repo also offers a separate (and optional) JavaScript function for loading stylesheets dynamically. As a primary pattern, we recommend loading asynchronous CSS like this from HTML. The loadCSS.js file exposes a global loadCSS function that you can call to load CSS files programmatically, if needed. This is handy for cases where you need to dynamically load CSS from script. The code above will insert a new CSS stylesheet link after the last stylesheet or script that it finds in the page, and the function will return a reference to that link element, should you want to reference it later in your script.