Site Compatibility and IE8
The Internet Explorer team today posted details that IE8’s Compatibility Mode (replicating IE7) will not render sites exactly as IE7 does.
We strive to make Compatibility View behave as much like IE7 as possible, but we do make exceptions. Many of these exceptions enable improved security and accessibility features immediately, even for sites that have not yet migrated to IE8 Standards Mode.
Repeat the mantra and stay sane, web sites do not need to look exactly the same in every browser
.