How can I extract this text(the one in bold) and change it into a variable called $videoid. For example

http://www.youtube.com/watch?v=IDiOX0UbHbg

and put it here

The video id of this video is $videoid

omo_to_dun:

I am assuming that you are using PHP, given the leading dollar sign in the variable.

   function queryValue($url) {
      return substr(strstr($url, 'v='), 2);
  }

  $videoid = queryValue("
https://www.youtube.com/watch?v=IDiOX0UbHbg");

Thank you so much. I figure out another way of doing it but

$websitead = '
https://www.youtube.com/watch?v=IDiOX0UbHbg';
$websitead = str_replace('http://www.youtube.com/watch?v=','',$websitead) ;
echo $websitead .'<br/>';

Once again I thank you for your help and reply.

The code omo_to_dun gave you is better.

Your will fail in many ways, what if www. was removed?
Besides it it too bulky, but can server for the time sha