var length=$('.box span').length;
function getLocArr(num) {
  var arr = [];
  var r = 200;
  var du = 360 / num;

  for (var times = 0; times < num; times++) {
    var hudu = (2 * Math.PI / 360) * (du * times - 180);
    var x = Math.sin(hudu) * r + r;
    var y = Math.cos(hudu) * r + r;
    arr.push(x + "-" + y);
  }

  return arr;
}
$('.box span').each(function(){
  var index=$(this).index();
  $(this).css({
    top:getLocArr(length)[index].split('-')[0]+'px',
    left:getLocArr(length)[index].split('-')[1]+'px',
  })
})