Rule 8: Make JavaScript and CSS External(Chapter 8 of High performance Web Sites)
In Raw Terms, Inline Is Faster
The fewer page views per user, the stronger the argument for inlining JavaScript and
CSS.
If every page on your site uses the same JavaScript and CSS, using external files will
result in a high reuse rate for these components.Using external files becomes more
advantageous in this situation because the JavaScript and CSS components are
already in the browser’s cache while users navigate across pages.
The fewer page views per user, the stronger the argument for inlining JavaScript and
CSS.
If every page on your site uses the same JavaScript and CSS, using external files will
result in a high reuse rate for these components.Using external files becomes more
advantageous in this situation because the JavaScript and CSS components are
already in the browser’s cache while users navigate across pages.
