A much leaner coding schema is needed to achieve compliance. The following code appears to do the job, maximising browser compatibility and compliance with XHTML Strict:
<object type="application/x-shockwave-flash" data="slide3.swf" width="800" height="480">
<param name="movie" value=" slide3.swf" />
</object>
This coding removes the need for an <embed> object altogether and works even if there is no slide3.gif file present.
For a YouTube movie, the equivalent lean code looks like this:
<object type="application/x-shockwave-flash" style="width:425px; height:350px;"
data="http://www.youtube.com/v/jV9YM3gNKOU">
<param name="movie" value="http://www.youtube.com/v/jV9YM3gNKOU" /></object>
Or if you want to test it, cut and paste the following complete HTML page:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>My Lean Embedded YouTube Movie</title>
<meta name="created" content="Sun, 14 Feb 2010 22:23:53 GMT" />
<meta http-equiv="content-type" content="text/html;charset=utf-8" />
<meta name="description" content="" />
<meta name="keywords" content="" />
</head>
<body>
<object type="application/x-shockwave-flash" style="width:425px; height:350px;"
data="http://www.youtube.com/v/jV9YM3gNKOU">
<param name="movie" value="http://www.youtube.com/v/jV9YM3gNKOU" /></object>
</body>
</html>
These code routines have been tested with modern versions of Internet Explorer and Firefox, as well as validated using the W3C validator, and should ensure maximum compatibility and accessibility for your pages.