function t1(){
  jQuery("#blinker").animate({ 
    opacity: 0,
  }, 1000 );
}
function t2(){
  jQuery("#blinker").animate({ 
    opacity: 1,
  }, 1000 );
}
runT1 = true;
function rr() {
  if (runT1) {
    t1();
  } else {
    t2();
  }
  // toggle between 2 fns
  runT1 = !runT1;
  setTimeout("rr()", 500);
}
rr();