RefTagger is a free product by Logos Software that turns Bible references on your website into hyperlinks that you can hover over and a pop-up of the scripture verse shows.
Hover your mouse over the following reference and you will see what I mean — 1Joh 3:6.
Current this software supports NIV, NASB, KJV, ESV, ASV, NLT, NKJV, YLT, DARBY, NIRV, and TNIV. I have set my blog to default to KJV, but I can add the version after the scripture and it will show that version.
Here are some examples.
1Joh 3:6 NIV, 1Joh 3:6 NASB, 1Joh 3:6 KJV, 1Joh 3:6 ESV, 1Joh 3:6 ASV, 1Joh 3:6 NLT, 1Joh 3:6 NKJV, 1Joh 3:6 YLT, 1Joh 3:6 DARBY, 1Joh 3:6 NIRV, 1Joh 3:6 TNIV.
When this software was originally released in Feb 27th 2008, it hyperlinked the scriptures to BibleGateway.com. A couple of months later on May 13th, 2008, Logos Software upgraded RefTagger so that instead of clicking a link to navigate to another web page, then you could immediately see the text of the passage in a pop-up window. A few months later on Aug 1st, 2008, they added an additional feature where you could customize the pop-up window style via CSS code.
I researched scripture pop-ups back in Aug 2008 and installed The Holy Scripturizer. That plug-in inserted the scriptures into the text and on big files like How to Become More Christ-like, it took 20 seconds to load because of that. I ended up disabling that plug-in.
When I found RefTagger this morning, I was very happy to see it has everything I wanted, and installed it on my blog before I headed to work.