How I can add EMBED?

I do this

<iframe allowtransparency=”true” width=”485" height=”402" src=”//scratch.mit.edu/projects/embed/49770444/?autostart=false” frameborder=”0" allowfullscreen></iframe>

it is not work.

I do this

<iframe width=”560" height=”315" src=”https://www.youtube.com/embed/PjMbqlxdun0" frameborder=”0" allowfullscreen></iframe>

I is not work too.

I do this

<div class=”storify”><iframe src=”//storify.com/squalius/scratch-2–0-programming-making-games-and-cartoons/embed?border=false” width=”100%” height=”750" frameborder=”no” allowtransparency=”true”></iframe><script src=”//storify.com/squalius/scratch-2–0-programming-making-games-and-cartoons.js?border=false”></script><noscript>[<a href=”//storify.com/squalius/scratch-2–0-programming-making-games-and-cartoons” target=”_blank”>View the story “Scratch 2.0 Programming. Making games and cartoons.” on Storify</a>]</noscript></div>

Help Me!