change javascript file with mod

[sivaci2754]

Can you guys explain what is the best method to modify javascript file inside Themes directory with mod ?

PS: I want to write mod for this: https://www.simplemachines.org/community/index.php?topic=582391.msg4126225#msg4126225

[Diego Andrés]

The attachments don't have an upload button anymore, making that edit for that is now pointless.

Answering the question, the mod would be like any other mod that makes a file edit, adding operations/instructions to the xml file.