In these days I have drawn attention to videos that play automatically as soon as you open the post, I saw him first in a forum where I felt a little uncomfortable this option, but in a blog is perfect place to provide a proper atmosphere for given post. That is why I gave myself the task of searching and found the way to go, but all this before Youtube simplify the code, which is why I started the task of testing various possibilities.
Here is the one that I found in a forum, I cant remember where i found it, had a mistake to want to put the ending "& autoplay = 1" after the URL code. I suppose many already know how to acquire the code, we click on the Youtube page in the video at our option "Embed ", then a window will open where we give you the code, in this case something so will appear
<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/Dfl9UHWBpk0" frameborder="0" allowfullscreen></iframe>
The trick itself is to add the following code in quotes as it is after the video URL: "?rel=0&autoplay=1" to make it as shown below:
<iframe title="YouTube video player" width="640" height="390" src="http://www.youtube.com/embed/Dfl9UHWBpk0?rel=0&autoplay=1" frameborder="0" allowfullscreen></iframe>
And that's all, now we only get you where going to put it, in my case to my blog, creating a "new post" on blogger, putting the tab "Edit HTML" there we stuck with the changes made, changing the green number modify the width and height of the window according to our requirements. Anyway I hope you like it but me and leave me a comment.