On Internet Explorer 8, on pages where there are comments count tags like <fb:comments-count href="<%= item_url(@item) %>"></fb:comments-count>, there will be error in Internet Explorer 8.
Could not set innerHTML: unknown runtime error.
Line: 40, Character: 327
http://connect.facebook.net/en_US/all.js
All other Facebook plugins (like button, comments box) works as expected.
I found out that the facebook namespace declaration have to be at the head level.
I changed from
<html>
<head prefix="og: http://ogp.me/ns# fb: http://ogp.me/ns/fb# object: http://ogp.me/ns/object#">
to
<html xmlns:fb="http://ogp.me/ns/fb#">
<head prefix="og: http://ogp.me/ns# object: http://ogp.me/ns/object#">
and the errors disappeared.
I was following Open Graph namespace declaration: HTML with XMLNS or head prefix? but the use-prefix-all-the-way clearly has some issue with ie8.
Update
I realized that I am also at fault in using the <fb:comments-count> tag by mistake, while I was using the HTML5 <div class="fb-comments-count"> tag in all other places.
If I leave the namespace declaration as it was, but use the correct HTML5 comments tag, then error will also disappear too.
