T.V
- You just need to add the argument &autoplay=1 at the end of your embedded video link, like this :
<iframe width="420" height="315" src="https://www.youtube.com/embed/vr3x_RRJdd4" frameborder="0" allowfullscreen></iframe>
<iframe width="420" height="315" src="https://www.youtube.com/embed/vr3x_RRJdd4&autoplay=1" frameborder="0" allowfullscreen></iframe>