I have a fun story.<p>IE10 and below have two modes. &quot;Browser&quot; mode, which means the IE10, IE9, IE8, IE7  rendering engines. &quot;Document&quot; mode which means the engine treating the page like it was meant for IE9, IE8, IE7 etc. Or so it says.<p>Confused? Take a look at this chart:<p><a href="https:&#x2F;&#x2F;i-msdn.sec.s-msft.com&#x2F;dynimg&#x2F;IC780294.jpg" rel="nofollow">https:&#x2F;&#x2F;i-msdn.sec.s-msft.com&#x2F;dynimg&#x2F;IC780294.jpg</a><p>More confused? So was and am I. I don&#x27;t fully understand document mode and I suspect Microsoft doesn&#x27;t either. Likely the reason they deprecated the moment Windows 10 came out[1]<p>So what&#x27;s the problem? Well, even though a web page would render fine in IE9, IE9 could look at it, take issue with your markup, and then, surprise! Your user sees it like it&#x27;s IE7... using the IE9 rendering engine.<p>For most web developers that needed to support IE, you basically always needed to insert a &lt;meta&gt; tag with a value of X-UA-Compatible in the &lt;head&gt; of your page. It forces the latest document mode, i.e., &quot;treat this page like a modern page and render it without being stupid.&quot; 99% of the time this is what you want. 1% of the time (the need for document mode) is when a page was so reliant on older browser quirks that it needs to be treated as an IE7 page.<p>Cool, that&#x27;s all we need right?<p>Enter oracle.com. In all versions of IE9, there is a hidden, built in compatibility mapping which will always force a certain document mode[2]. So even if your little page brings with it a valid meta tag and uses completely valid markup, IE9 will take look at its name on its blacklist, smile, pat your page on the head, and then shove it the trash compactor.<p>Smash. So IE9 forces a terrible document mode upon all pages on oracle.com and several other domains mode and Microsoft, to this days, says just about nothing about the hidden blacklist in their documentation. The only way I found this out was by searching &quot;oracle.com&quot; in all of IE9&#x27;s source code, whereupon I found the responsible XML file, the blacklist.<p>So what&#x27;s the solution?<p>Well, after some hair loss, I discovered the solution is to bring the X-UA-Compatible OUTSIDE of the &lt;head&gt; tag and put it right above the HTML one. In complete contrivance to everything Microsoft said in its documentation, and also normal browser logic.<p>... That, kids, is why IE9 and below needs to die.<p>[1]<a href="https:&#x2F;&#x2F;msdn.microsoft.com&#x2F;en-us&#x2F;library&#x2F;dn384051(v=vs.85).aspx" rel="nofollow">https:&#x2F;&#x2F;msdn.microsoft.com&#x2F;en-us&#x2F;library&#x2F;dn384051(v=vs.85).a...</a>