声明的jQuery函数不适用于新创建的项目

Question

This function replaces a <button> with an <input> and a <button> :

<button id="add3" class="button">Add...</button>



$(function(){
   $('#add3').click(function () {
      $(this).replaceWith('<input id="edit3" class="input" type="text" placeholder="Enter 3-rd option..." /><button id="add4" class="button">Add...</button>');
    });
 });

So when you press the Add... button, an input field appears and also another Add... <button>

The next thing I want to do, is replace the newly created Add <button> with just an <input> field, because the limit is 4 input fields. I would do this by running this function:

$(function(){
    $('#add4').click(function() {
        $(this).replaceWith('<input id="edit4" class="input" type="text" placeholder="Enter 4-th option..." />');
    });
});

But the thing is, it doesn't apply already stated functions to newly created elements, as I presume. Is there any way to make it run?

Thank you for your replies!

Answer 1

You need to use Event Delegation using .on()

http://jsfiddle.net/r2gCu/

$('#add3').click(function () {
      $(this).replaceWith('<input id="edit3" class="input" type="text" placeholder="Enter 3-rd option..." /><button id="add4" class="button">Add...</button>');
    });

 $(document).on('click','#add4' ,function() {
        $(this).replaceWith('<input id="edit4" class="input" type="text" placeholder="Enter 4-th option..." />');
    });

When you just bind a click event, it will be only bound to the existing DOM elements, so you want to bind the event to the parent element (ex:- i have used document but you can use the container that already exists like a div or something), and later any elements you add with the same selector with that container will have the event available by delegation.

From Jquery Docs

Delegated events have the advantage that they can process events from descendant elements that are added to the document at a later time. By picking an element that is guaranteed to be present at the time the delegated event handler is attached, you can use delegated events to avoid the need to frequently attach and remove event handlers. This element could be the container element of a view in a Model-View-Controller design, for example, or document if the event handler wants to monitor all bubbling events in the document. The document element is available in the head of the document before loading any other HTML, so it is safe to attach events there without waiting for the document to be ready.