string ss = "<!doctype html>" + "<html><head><meta bgcolor=\"black\" name=\"viewport\" content=\"width=1080, initial-scale=1.0, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0\" /><title></title></head><body style=background-color:black;>" + "<iframe \"background-color:black\" id=\"ytplayer\" type=\"text/html\" width=\"1080\" height=\"700\" src=\"https://www.youtube.com/embed/?rel=0&autoplay=1&loop=1&modestbranding=1&playlist=" + youtubeIDS + "&playsinline=1&controls=0\" frameborder=\"0\" allowfullscreen>" + "</body></html>"; webbrowser.NavigatetoString(ss);but not able to Autoplay the Video.