Show youtube video on your webpage with simple url

For college project I was building simple website. One of future was share youtube video I used iFrame, but it not worked. simple two lines fixed problem:

$videoUrl = full video url from browser 

$video = str_replace("https:","",$videoUrl);

$video = str_replace("watch?v=","embed/",$video);


echo '<iframe height="315" src="'.$video.'" width="420"></iframe>';

Maybe it will be useful for somebody.