Inline mode with "double-click" to edit

I want to present my HTML content as a easily viewed and SELECTABLE block of text.  Then if the user clicks a button, OR double-clicks... the "inline edit" mode engages.  I can build something custom to do this, I think - but before I do I wanted to see if anyone knew of an easy way to :

1.) Disable inline edit on single-click

2.) Enable it on double-click

3.) Enable it on the click of an outside "edit" button I create.

Thanks!