how to get:
WA4nNDfQ0wA
form this code:
<p>some text here ...</p>
<iframe width="640" height="360" src="//www.youtube.com/embed/WA4nNDfQ0wA?feature=player_embedded" frameborder="0" allowfullscreen></iframe>
<div>some text here ...</div>
<iframe width="640" height="360" src="//www.youtube.com/embed/9gypDWA6r2s?feature=player_embedded" frameborder="0" allowfullscreen></iframe>
by using php?