function See(idt)
   {
     Cover();
     document.getElementById(idt).style.display = "inline";

   }

function Cover()
   {
	 document.getElementById('video0').style.display = "none";
     document.getElementById('video1').style.display = "none";
	 document.getElementById('video2').style.display = "none";
	 document.getElementById('video3').style.display = "none";
   }