The ESV bible and the ESV plugin on this page
Well, now some of you would have seen the pretty tooltip pop-ups when you mouse over a reference to a verse. This is much for the readers sake. Why ESV? Simple, there’s no online KJV or NKJV bible that has an API which will allow this kinda functions. While we can debate over bible versions, it would be easier to just go to biblegateway and search up the verse in your favorite version. I do not favour the ESV over the KJV or NKJV, the 3 are pretty much identical except when it comes to certain verses where some manuscripts differ. I like the ESV because they include everything (the stuff of conflict) in the footnotes. So in effect, you have everything but they tell you why some stuff is not included in the main text of the ESV. Hope it makes things much more readable.