Issue on Processing Array Items Into a Div

Issue on Processing Array Items Into a Div

can you please take a look at this code and let me know why I am not able to add the array Items into the .box? I already used the .text() and .html() 

  1. var letters = [];
  2. var str = "A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
  3. var letters = str.split(",");

  4. for (var j = 0; j < letters.length; j++) {
  5.     $(".box").html(letters[j]);
  6.  }
but they only add the last item "Z" into the box.