const videoId = getId('http://www.youtube.com/watch?v=zbYf5_S7oJo');

function getId(url) {

    const regExp = /^.*(youtu.be\/|v\/|u\/\w\/|embed\/|watch\?v=|&v=)([^#&?]*).*/;

    const match = url.match(regExp);

 

    return (match && match[2].length === 11)

      ? match[2]

      : null;

}

   

const videoId = getId('http://www.youtube.com/watch?v=zbYf5_S7oJo');

const iframeMarkup = '<iframe width="560" height="315" src="//www.youtube.com/embed/'

    + videoId + '" frameborder="0" allowfullscreen></iframe>';

 

console.log('Video ID:', videoId)