Copy text in a box with a button?

[Slendy]

I'm trying to add a button that copies generated text from a text box. Is there any way to do that?


f-ar.boards.net/page/character-app

There's a link to the thing itself, when you hit the generate button it puts the text in the box however I want to have a button so that the text will be copied so people can just paste it in to a new thread.

I've been fiddling with it but I can't seem to get it to work.