Что применимо для использования JavaScript-геттеров? [Дубликат]

var body = $("body");
var btns = $("button");
var btnB = $("<button>B</button>");
// `<button>B</button>` is not yet in the document.
// Thus, `$("button")` gives `[<button>A</button>]`.
// Only `<button>A</button>` gets a click listener.
btns.on("click", function () {
  console.log(this);
});
// Too late for `<button>B</button>`...
body.append(btnB);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button>A</button>

var body = $("body");
var btnB = $("<button>B</button>");
var btnC = $("<button>C</button>");
// Listen to all clicks and
// check if the source element
// is a `<button></button>`.
body.on("click", function (ev) {
  if ($(ev.target).is("button")) {
    console.log(ev.target);
  }
});
// Now you can add any number
// of `<button></button>`.
body.append(btnB);
body.append(btnC);

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button>A</button>

var i = 11;
var body = $("body");
body.on("click", "button", function () {
  var letter = (i++).toString(36).toUpperCase();
  body.append($("<button>" + letter + "</button>"));
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<button>A</button>