var c = 0
$foo = $('#foo')
function timedCount()
{
  $foo.html(c)
  c=c+1
  $foo.addClass('big')
}
$foo.on('transitionend', function () {
    console.log('789')
    if(!$foo.hasClass('big')){
      if(c<=10){
        timedCount()
      }
      else{
       console.log('123')
      }
    }
    else{
      $foo.removeClass('big')
      console.log('456')
    }
  })
$('#btn').on('click',function(){
    timedCount()  
})