var n = 0;
var a = 0;


function blinker()
{
  
  objekt=document.getElementById('jumper');
  if(n==0)
  {
    objekt.style.display = "block";
    n=1;
  } 
  else
  {
    objekt.style.display = "none";
    n=0;
  }
  timer = window.setTimeout('blinker()', 500);
  
 a = a + 1;
  
 if ( a >= 12 )
 {
 	if(timer)
 		{
				window.clearTimeout(timer);
				objekt.style.display = "block";
		}
 	}
  
}