### Author:  [@craigconstantine](https://meta.discourse.org/u/craigconstantine)
#### Post date: [May 13, 2021, 12:36pm UTC](https://meta.discourse.org/t/interaction-among-theme-component-theme-javascript-and-previews/190303/1 "2021-05-13T12:36:50Z")
# j/s
I have some custom j/s in my theme. (It’s my solution to, [Interactive SVG using \? - #9 by craigconstantine](https://meta.discourse.org/t/interactive-svg-using-object/173747/9) ) Eventually, I’ll move the j/s to a Git repo, and install it as a proper Theme component. For now, I simply have the j/s pasted into my Theme’s header. I suppose, this problem might go away if I installed this j/s as a proper component, but it doesn’t smell that way to me.
My j/s modifies the DOM before it’s sent to the browser…
```
api.decorateCooked(
$elem => $elem.children('.cooked div[data-custom="umbdv"]').umbdv(),
{ id: 'umbdv' }
);
```
# In action…
It selects appropriate `
### Author:  [@david](https://meta.discourse.org/u/david)
#### Post date: [May 13, 2021, 1:35pm UTC](https://meta.discourse.org/t/interaction-among-theme-component-theme-javascript-and-previews/190303/2 "2021-05-13T13:35:27Z")
Unfortunately there isn’t a javascript API for modifying the ‘excerpts’ of topics in the topic list. Theme components also do not have any access to server-side rendered content (i.e. emails) for security reasons. If you wanted to modify emails, you would have to use a plugin.
However, I wonder if we can solve this in a different way. Right now you are pasting something like this in the composer:
```html
/vmm/longstringhere
```
Instead, you could do something like this:
```html
fallback content for emails/excerpts
```
Or if you’re feeling super fancy, you could use [the generic bbcode wrapper](https://meta.discourse.org/t/generic-bbcode-wrapper-for-theme-components/123516) to do it
```plaintext
[wrap=umbdv longstring="/vmm/longstringhere"]
Fallback content
[/wrap]
```
That will automagically generate a div like
```plaintext
```
Then you will need to tweak your theme component code so that it deletes the fallback content, and replaces it with whatever you want to show.
---
### Author:  [@craigconstantine](https://meta.discourse.org/u/craigconstantine)
#### Post date: [May 13, 2021, 1:53pm UTC](https://meta.discourse.org/t/interaction-among-theme-component-theme-javascript-and-previews/190303/3 "2021-05-13T13:53:26Z")
…oooooooooooh, that would do it. I’ll tinker and report back. 🙂
---
### Author:  [@craigconstantine](https://meta.discourse.org/u/craigconstantine)
#### Post date: [May 14, 2021, 12:02pm UTC](https://meta.discourse.org/t/interaction-among-theme-component-theme-javascript-and-previews/190303/4 "2021-05-14T12:02:58Z")
…yeah, works purrfectly @david, thanks!
---
### Author:  [@pfaffman](https://meta.discourse.org/u/pfaffman)
#### Post date: [May 14, 2021, 4:37pm UTC](https://meta.discourse.org/t/interaction-among-theme-component-theme-javascript-and-previews/190303/5 "2021-05-14T16:37:19Z")
Sometimes the ❤ just isn’t enough. This is a great answer, and I’m really close to understanding javascript and CSS well enough to `d-wrap` my head around it. 🍻