Support dynamic scripts which are added to the DOM before src is set #975
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This should load the "src.js":
```
const s = document.createElement('script');
document.getElementsByTagName('body')[0].appendChild(s);
s.src = "src.js"
```
Notice that src is set AFTER the element is added to the DOM. This PR enables
the above, by
1 - skipping dynamically added scripts which don't have a src
2 - trying to load a script whenever `set_src` is called.
(2) is safe because the ScriptManager already prevents scripts from being
processed multiple times.
Additionally, not only can the src be set after the script is added to the DOM,
but onload and onerror can be set after the src:
```
s.src = "src.js"
s.onload = ...;
s.onerror = ...;
```
This PR also delays reading the onload/onerror callbacks until the script is
done loading.
This behavior is seen on reddit.
krichprollsch
approved these changes
Aug 26, 2025
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This should load the "src.js":
Notice that src is set AFTER the element is added to the DOM. This PR enables the above, by
1 - skipping dynamically added scripts which don't have a src 2 - trying to load a script whenever
set_srcis called.(2) is safe because the ScriptManager already prevents scripts from being processed multiple times.
Additionally, not only can the src be set after the script is added to the DOM, but onload and onerror can be set after the src:
This PR also delays reading the onload/onerror callbacks until the script is done loading.
This behavior is seen on reddit.