Confirm if string is a YouTube URL, strip the youtube ID, and convert the url to a specific format and security.

isYouTube

var youTubeID;
var videoURL = "http://youtube.com/v/youtubeid"

if ( isYoutubeFile( videoURL ) == true ) {
  //do something
}

function isYoutubeFile(vidURL) {
  //console.log( "javascript: isYoutubeFile: vidURL: " +vidURL );
  var videoURL;
	if ( vidURL.toLowerCase().indexOf( "http://www.youtube.com/v/" ) == 0 ) {
		youTubeID = vidURL.substr( 25, 11 );
		if ( "https:" == document.location.protocol ) {
			videoURL = "https://www.youtube.com/v/" + youTubeID;
		} else {
			videoURL = "http://www.youtube.com/v/" + youTubeID;
		}
		return true;
	}
	if ( vidURL.toLowerCase().indexOf( "http://www.youtube.com/watch?v=" ) == 0 ) {
		youTubeID = vidURL.substr( 31, 11 );
		if ( "https:" == document.location.protocol ) {
			videoURL = "https://www.youtube.com/v/" + youTubeID;
		} else {
			videoURL = "http://www.youtube.com/v/" + youTubeID;
		}
		return true;
	}
	if ( vidURL.toLowerCase().indexOf( "https://www.youtube.com/v/" ) == 0 ) {
		youTubeID = vidURL.substr( 26, 11 );
		if ( "https:" == document.location.protocol ) {
			videoURL = "https://www.youtube.com/v/" + youTubeID;
		} else {
			videoURL = "http://www.youtube.com/v/" + youTubeID;
		}
		return true;
	}
	if ( vidURL.toLowerCase().indexOf( "https://www.youtube.com/watch?v=" ) == 0 ) {
		youTubeID = vidURL.substr(32, 11);
		if ( "https:" == document.location.protocol ) {
			videoURL = "https://www.youtube.com/v/" + youTubeID;
		} else {
			videoURL = "http://www.youtube.com/v/" + youTubeID;
		}
		return true;
	}
	return false;
}