Mechanism of delta-loading
Usually, you will have different CSS’s and scripts on the various pages.
Some CSS’s and scripts tags will be page-specific while others are common to all pages.
Delta-loading means that:
- CSS’s and scripts that are genuinely new to a page (page-specific) will be loaded dynamically
- CSS’s and scripts that are common to both pages will remain in memory
- CSS’s and scripts that are genuinely old to a page (page-specific) will be unloaded dynamically
- all CSS’s and scripts with
data-class="always"are always loaded, if the URL remains the same!
Inline scripts and style tags
…can now be loaded smartly
Preserving order of the DOM
From version 6.4.0, the order of the scripts in the DOM, whether inline or external is preserved, when delta-loading. That means you can steer the order of loading by interspersing inline and external scripts, which is probably, what you expected intuitively…
…is performed without an extra GET! (analysing the DOM tree on DOMReady)
Delta-loading described at Wikipedia
see also: Delta-loading in HTTP at Wikipedia