Do modern browsers support DOCTYPE?
If you use obsolete attributes or tags <center>, <font color="red">or <td valign="top">etc. in XHTML 1.0 Strict (without des attributes), modern browsers (I will use Chrome as an example) still notice and use them.
If you use HTML5 <video>on the XHTML 1.0 Strict DOCTYPE, Chrome will still recognize it - it's not like they programmed it to nothing. I tested the worst obsolete, uppercase and incorrect attribute code that I could write with HTML5 audio using XHTML 1.0 Strict DOCTYPE in Chrome, and it looked flawless.
Here the code I tested works flawlessly in Chrome (red bg, centered, audio playback):
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>Do browsers care about the DOCTYPE?</title>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8" >
</head>
<body bgcolor=#ff0000>
<CENTER>
<table cellpadding="0" cellspacing=0>
<tr><td valign=top>test</td></tr>
</table>
</CENTER>
and some HTML5 audio..
<audio autoplay>
<source src="http://www.duncannz.com/resources/sound/alarm.mp3" type="audio/mp3">fallback text</audio>
</body>
</html>
, : (: , IE) - - - DOCTYPE? ?
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