<div id="videocontent" class="vep-videocontent">
<iframe width="640" height="360" src="http://www.youtube.com/embed/Bzj1UKePBOE?fs=1&feature=oembed&wmode=transparent&autoplay=1" frameborder="0" allowfullscreen=""/></iframe>
</div>
<script type="text/javascript">
var video = document.getElementById('videocontent')
var a = video.getElementsByTagName('iframe')[0].src;
a = a.replace(/\?.*$/,'')
alert(a)
</script>