var won = 1000000;

putCom(won);

function putCom(value){
  if(value.length < 1) return;
  var rv = '', b = '', i=pv.length-1, a = 1, pv = value.toString().trim();
  while(i>-1){
    b = pv[i]+b;
    if(a%3==0){
      rv = ','+b+rv;
      b = '';
    }
    if(i==0 && b.length>0) rv = b+rv;
    a++, i--;
  }
  if(rv[0]==',') rv = rv.substring(1, rv.length);

  return rv;
}