Flash used to be the only thing that worked, cross-browser.<p>Chrome, I know for sure, changed their minds several times on whether they would allow it...security model thing, you could make it work only by tweaking some internal chrome setting.<p>The sales pitch at  <a href="https:&#x2F;&#x2F;clipboardjs.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;clipboardjs.com&#x2F;</a> makes it sound like perhaps things have changed enough that a reasonable cross-browser solution is possible now.