Backport #27267 by @silverwind
1. Dropzone attachment removal, pretty simple replacement
2. Image diff: The previous code fetched every image twice, once via
`img[src]` and once via `$.ajax`. Now it's only fetched once and a
second time only when necessary. The image diff code was partially
rewritten.
Co-authored-by: silverwind <me@silverwind.io>
When doing the refactoring:
* #22950
I added some debug mode code (assertShown) to help to catch bugs, it did
catch some bugs like:
* #23074
If it has been proved that there is no more bugs, this assertion could
be removed easily and clearly.
Feel free to decide when to remove it (feel free to convert it from
Draft to Ready for Review).
cc: @silverwind
Close#22847
This PR:
* introduce Gitea's own `showElem` and related functions
* remove jQuery show/hide
* remove .hide class
* remove inline style=display:none
From now on:
do not use:
* "[hidden]" attribute: it's too weak, can not be applied to an element
with "display: flex"
* ".hidden" class: it has been polluted by Fomantic UI in many cases
* inline style="display: none": it's difficult to tweak
* jQuery's show/hide/toggle: it can not show/hide elements with
"display: xxx !important"
only use:
* this ".gt-hidden" class
* showElem/hideElem/toggleElem functions in "utils/dom.js"
cc: @silverwind , this is the all-in-one PR
