code: func Splice(obj *js.Object, index, howmany int, items ...interface{}) *js.Object {
  	args := []interface{}{index, howmany}
  	args = append(args, items...)
  	return obj.Call("splice", args...)
  }
docs: //array slice operation
  // index	required,position to add to(remove from),negative means reverse
  // howmany	required,number of items to remove, 0 means no remove
  // items... optional,add new items to the array