function start() {
    var t1 = document.getElementById('t1');
  var t2 = document.getElementById('t2');
  var k = document.getElementById('k');
  var zeit ="10s";
  // animation starten

  t1.style.MozAnimationName = "tuer1";
  t1.style.MozAnimationDuration = zeit;
  t1.style.MozAnimationIterationCount = "1";
  t1.style.MozAnimationTimingFunction = "linear";
  t1.style.MozAnimationFillMode = "forwards";
  t2.style.MozAnimationName = "tuer2";
  t2.style.MozAnimationDuration = zeit;
  t2.style.MozAnimationIterationCount = "1";
  t2.style.MozAnimationTimingFunction = "linear";
  t2.style.MozAnimationFillMode = "forwards";
  k.style.MozAnimationName = "knopf";
  k.style.MozAnimationDuration = zeit;
  k.style.MozAnimationIterationCount = "1";
  k.style.MozAnimationTimingFunction = "linear";

  t1.style.webkitAnimationName = "tuer1";
  t1.style.webkitAnimationDuration = zeit;
  t1.style.webkitAnimationIterationCount = "1";
  t1.style.webkitAnimationTimingFunction = "linear";
  t1.style.webkitAnimationFillMode = "forwards";
  t2.style.webkitAnimationName = "tuer2";
  t2.style.webkitAnimationDuration = zeit;
  t2.style.webkitAnimationIterationCount = "1";
  t2.style.webkitAnimationTimingFunction = "linear";
  t2.style.webkitAnimationFillMode = "forwards";
  k.style.webkitAnimationName = "knopf";
  k.style.webkitAnimationDuration = zeit;
  k.style.webkitAnimationIterationCount = "1";
  k.style.webkitAnimationTimingFunction = "linear";

}

@-webkit-keyframes 'tuer1' {
   from       {width: 50%;}
   to         {width: 0%; visibility:hidden; }
}

@-o-keyframes 'tuer1' {
   from       {width: 50%;}
   to         {width: 0%; visibility:hidden;}
}
@-moz-keyframes 'tuer1' {
   from       {width: 50%;}
   to         {width: 0%; visibility:hidden;}
}
@keyframes 'tuer1' {
   from       {width: 50%;}
   to         {width: 0%; visibility:hidden;}
}

@-webkit-keyframes 'tuer2' {
   from       {left: 50%;}
   to        {left: 100%; width: 0px; visibility:hidden;}



}