don't use executeJavaScript() (fix for PR #107)
don't use executeJavaScript() (fix for PR #107)

It’s not *that* much cleaner, but executeJavaScript() feels too much
like eval().

cc @flet

michaelgeorgeattard/webtorrent-desktop,feross/webtorrent-desktop,webtorrent/webtorrent-desktop,feross/webtorrent-app,yciabaud/webtorrent-desktop,webtorrent/webtorrent-desktop,yciabaud/webtorrent-desktop,feross/webtorrent-desktop,feross/webtorrent-app,michaelgeorgeattard/webtorrent-desktop,webtorrent/webtorrent-desktop,michaelgeorgeattard/webtorrent-desktop,feross/webtorrent-desktop,yciabaud/webtorrent-desktop,feross/webtorrent-app