Youtube video control troubleshooting

hi, i use this code

var video = $("<iframe/>");

sym.$("video").append(youtubevid);

youtubevid.attr('type','text/html');

youtubevid.attr('width','640'); //my "video" symbol is 640x480

youtubevid.attr('height','480'); //my "video" symbol is 640x480

youtubevid.attr('src','//www.youtube.com/mylink');  // url/Video_Id

youtubevid.attr('frameborder','0');  

youtubevid.attr('allowfullscreen','0');

all goes ok, but control don't function! i can see control bar (play, pause, vol, etc) but don't go! the unic button is the big "play" at the center of the video.

what's wrong?

tnx!!!