For those who broadcast YouTube in their blog before, you should know that the YouTube embed tag is actually not XHTML valid, it's because the <embed> had been deprecated from XHTML 1.0.
By default the YouTube embed tag should looks something like this:
HTML:
<object width="425" height="350">
<param name="movie" value="http://www.youtube.com/v/m_Dxp5HQNIA"></param>
<param name="wmode" value="transparent"></param>
<embed src="http://www.youtube.com/v/m_Dxp5HQNIA" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350">
</embed>
</object>
<param name="movie" value="http://www.youtube.com/v/m_Dxp5HQNIA"></param>
<param name="wmode" value="transparent"></param>
<embed src="http://www.youtube.com/v/m_Dxp5HQNIA" type="application/x-shockwave-flash" wmode="transparent" width="425" height="350">
</embed>
</object>
But it contain the <embed> HTML tag which is not allow in XHTML 1.0 Strict, so in order to make it pass the validation, i change the above code to something like this:
HTML:
<object type="application/x-shockwave-flash" width="425" height="350" data="http://www.youtube.com/v/m_Dxp5HQNIA"><param name="movie" value="http://www.youtube.com/v/m_Dxp5HQNIA" /></object>
YouTube plays well with the new tag, and it doesn't have the <embed> tag, which is XHTML 1.0 Strict valid!
