Modifying the Spoiler plugin to act like WordPress "More..."
First thanks to @peregrine and @hgtonight who helped me get to the point of being able to make this change.
I wanted a functionality similar to the "More..." button seen in many WordPress blogs. I wanted it to be minimalistic - small out of the way button, no special border and backgrounds, and to say "More..." and "...Less".
I had to slightly change every piece of the plugin (though these are minor changes):
1) In the plugin code class.spoilers.plugin.php I had to change the $Attribution variable to hide the text preceding the button and the button text. The change is in protected function SpoilerCallback a follows:
$Attribution = T('More... %s');
$Attribution = T(' %s');
2) Change the Javascript code to place the "More..." and "...Less" text on the button Lines 24, 40 and 42):
SpoilerButton.value = 'More...';
SpoilerButton.val('More...');
SpoilerButton.val('...Less');
3) Change the CSS file to have the desired appearance.
div.UserSpoiler div.SpoilerTitle {
font-weight: bold;
}
div.UserSpoiler div.SpoilerTitle span {
color:red;/*PA color: white;*/
}
div.UserSpoiler input {
display: inline;
font-weight: bold;
margin: 0;
padding: 0px 4px;/*PA 2px 5px; */
text-decoration: none;
cursor: pointer;
color:green;/*PA color: #1E79A7; */
text-transform: capitalize; /*PA */
}
div.SpoilerTitle input {
display: inline;
font-weight: bold;
text-decoration: none;
cursor: pointer;
color:blue;/*PA color: #1E79A7; */
float:right;/*PA */
text-transform: capitalize; /*PA */
}
div.UserSpoiler div.SpoilerText {
display: none;
}
Attached screens show how it looks



[spoiler]
The only thing I am not convinced of is the issue of posting the modded plugin. I understand that for the developer and other experienced modders it is preferable to see the changes posted (and explained) in this discussion. But I see so many newbies (like me) who are not yet programmers and who would find benefit from ready-to-use modifications.
That said, not to upset anyone I am posting below the changes as well as screen shots but not the modified plugin[/spoiler]

Comments
Eventually we'll do this: https://github.com/vanilla/vanilla/issues/2426
Thanks @linc. I hope one of the styles you will support will be a "More..." similar to the above.